What do you mean by latest file? Which file is giving you trouble to download?
Ok, so here is the process I went through:
1.) Went to google and typed in this: "redsn0w beta for iOS4"
2.) I then clicked on the first link, which is this: "http://www.iphonedownloadblog.com/2010/06/21/jailbreak-iphone-3g-on-ios-4-with-redsn0w/"
3.) Then, I proceeded to follow this set of instructions:
How to Jailbreak iPhone 3G iOS 4
Step 1: Make sure you have the latest version of iTunes installed (iTunes 9.2).
Step 2: Download iOS 4 for iPhone 3G to your desktop from our iPhone downloads section.
Step 3: Update your iPhone to iOS 4 via iTunes.
Step 4: Download the latest version of RedSn0w from here.
Step 5: Point RedSn0w to the iOS 4 you downloaded in step 2.
Step 6: Select Install Cydia.
Step 7: Follow the onscreen instructions.
Step 8: Let RedSn0w do the hard work for you. Once jailbroken, your iPhone will reboot.
4.) With step 2, I went to the iPhone download section, and downloaded the ISPW for the "iPod Touch 2G, iOS4" (which took about 30 minutes)
5.) I then went to step 4 (skipping step 3, because my iPod has already been upgraded to iOS4), and proceeded to try and download the newest RedSn0w for Mac, and what I posted in my previous post is what happened when I clicked to download the newest RedSn0w. After that not working, I then downloaded the next-newest RedSn0w.
6.) After downloading RedSn0w, I then followed the instructions, and this is what I got: "Unable to recognize specified IPSW."
And that is as far as I got. Can you help? Thank you!!!