1. Jailbreaking allows unsigned code to run on iOS (Cydia and its features). Unlocking lets you use the phone on another carrier. When you jailbreak, you can install ultrasn0w in Cydia to unlock the phone if you are on the appropriate baseband (modem firmware). You can, however, unlock without jailbreaking by physical means by way of GEVEY SIM.
2. pod2g says a few more [days]. Jailbreakme.com has nothing to do with this.
1 - Unlocking is for using your iphone on other GSM carriers (ie. Sprint or ATT). JB is more for modifying your phone. (Just Google jailbreaking and you will get a ton of stuff).
Yeah you got plenty of reason to JB even if you are no unlocking.
Jailbreakme tool, required a very specific type of exploit (userland Exploits), which are usually hard to find, so those type of tools are a rare thing, in most cases the tool will require a computer to run.
There is not official ETA on the 4S Jailbreak but it is close, they are just testing it right now to avoid mayor bugs that could harm or slow down your system.
You can read this to help you understand better all the terms.
Jailbreak tools are for jailbreaking. Unlocking tools are for unlocking. They are two different thing. You will need to jailbreak first in order to unlock. 90% of the jailbreak tools weren't jailbreakme. Don't be lazy and learn.