Day After Update:
roxxette, thank you for that suggestion. Leaving the device plugged in, even though the MacOS Absinthe was at 100% complete and didn't really specify, seemed to cause everything to go through.
For people encountering problems, try this mini-guide. These are the EXACT steps I took (over the course of 20 or so minutes, not including the drive to the Apple Store so I could use their Mac):
Step 0) Backup your iPhone. And because I'm not sure if it helps (I've seen it suggested, and I did it and it didn't seem to hurt), disable your passcode lock if you use one. Also, turn your autolock to Never. You can always re-enable both after the process is done.
Step 1) Download absinth-mac-0.1.2-2.zip from here:
http://cache.greenpois0n.com/dl/absinthe-mac-0.1.2-2.zip
Step 1b) Since I
do not own a Mac and the
Windows client isn't out yet, I had to transfer the absinth-mac-0.1.2-2.zip to a USB flash drive and figure out where I could use a Mac. You can try your local Target, Apple Store, or buddy-down-the-street-with-a-Mac.
Step 1c) When you arrive at a Mac with your iPhone, iPhone cable, and flash drive with absinth on it, go ahead and plug in the flash drive and drag absinth-mac-0.1.2-2.zip to the Mac's Documents folder (or wherever, really). Then, go ahead and unplug the flash drive and plug in your iPhone.
Step 2) Make sure your iPhone is plugged in! Now double click the absinthe-mac-0.1.2-2.zip file, and when that opens, double click "Absinthe" (I'm typing this from a Windows computer, so I've forgotten
exactly what "Absinthe" looks like in the zip. It shouldn't be too hard to figure out). I believe it extracts at this point. Now look for a little green icon with a skull in it. It should be located right by / in the same directory as your absinthe-mac-0.1.2-2.zip file. Double click that.
Step 3) A window will appear, titled Chronic-Dev Absinthe. It should detect your iPhone within 5 seconds, and when it does the Jailbreak icon will light up. Click the Jailbreak button when this happens.
Step 4) And now begins the waiting.
Do not touch your phone during this process. This process will take upwards of 15 minutes, judging from my (and others) experiences. On your device, you'll note the little 'syncing' icon on your status bar. This is good, it means the jailbreak is working. At a later stage of the jailbreak, your iPhone screen will go black and display 'Restoring.' This is normal, it means you're proceeding according to plan. If you look on the Mac side of things, the Absinthe progress bar will detail that your iPhone will appear to be restoring. On that note, this website will show you all of the different phases this progress bar will display:
http://modmyi.com/content/6678-how-jailbreak-using-absinthe-0-1-os-x.html
Very handy if you want to know how far along you are in the process. It
will take a while.
Do not touch your phone during this process.
Step 5) When the Absinthe progress bar reaches 100%, the window should read "Almost done- just unlock the screen if necessary, then tap the 'Jailbreak' icon to finish. (It might be on a different homescreen, so don't give up looking!)"
At this point, start to cheer. You're about 10 seconds from being done! (provided you don't encounter any hiccups).
This is where I made the mistake of unplugging my device before tapping the Absinthe icon on my iPhone! Leave your iPhone plugged in while doing the next step!
Step 6) With your iPhone still plugged in, with the Absinthe window on the mac displaying 100% complete with that message I quoted above, unlock your iPhone and find the Absinthe app. When you find it, tap it. A white screen will appear, and it won't appear to be doing anything. Note the spinning wheel on your status bar. That means it is working. Now, at this point, one of four things can happen:
- The spinning wheel on the status bar disappears, but the screen stays white with no text at all on it. If this happens, close the app, double-click Home to open the switcher, hold your finger on the Absinthe icon to cause it to wiggle, and then tap the (-) icon to close it out. Then, tap the Absinthe icon to try again. Repeat as necessary until it works.
- At the top of the white screen, it says "Error establishing database connection." This is actually a good thing. If you're lucky, your iPhone will reboot at this point (I'd say within a minute of displaying "Error establishing database connection") and when it starts back up, the Absinthe app will be replaced with Cydia and you will be done.
- If you get "Error establishing database connection" and it doesn't automatically reboot (give it a minute to make absolutely sure it won't reboot), then close the Absinthe app and go into Settings. Go into General, into Network, into VPN, and there should be one listing in there titled "jailbreak." Go ahead and click VPN from Off to On. It will do a spinning wheel for a few seconds, then an "configuration error" dialog will appear. Now, I didn't have to actually use the VPN trick, but apparently at this point (if you've done everything else correctly) you click Home to go back to your homescreen. Your iPhone should automagically reboot (within several seconds, as described by other people) and when it starts up next, the Absinthe app will be replaced with Cydia and you will be done.
- OR, if on the white screen of the Absinthe app, a dialog error message pops up saying "Could not open the page because the server stopped responding", just go ahead and click Retry. I believe this is due to the high volume of people trying to do the same thing you are. If this error keeps happening as it was for me last night, or it finally goes through and shows "Error establishing database connection" but nothing happens after that and the VPN fix doesn't work, then restore from your backup and start the entire process over.
Step 7) And of course at this point provided everything worked and you're looking at a Cydia icon on your homescreen, you should launch Cydia and let it do its thing. It will cause your iPhone to reboot one last time, and then you can launch Cydia again and go from there. If you're new to Cydia, when it prompts a "Who are you?" just choose "User." Now you're good to go! Check out
http://jaxov.com/2012/01/top-10-best-cydia-sources-repos-of-2012/ for some awesome sources to add that will provide you with even more jailbroken goodness.
Good luck everyone! I hope this has helped. 
