Developing for a jailbroken iPhone, A to Z (iPhone 3.0)
Rockin 3.0
UPDATE: NEWGUIDE NEWGUIDE NEWGUIDE!
Vital iPhone stats for this post:
iPhone version: 3G (should work with 2G and 3GS)
iPhone OS version: 3.0 (rock the hizzouse!)
Jailbreak status: Jailbroken using Pwnage Tool.
The Goal: Get live on-device XCode debugging without being a paying ADC member. This time OS 3.0 style.
Hold on tight, 3.0 sdk info coming soon
UPDATE 7/11/09: Procedure working great: post here.
Everyone's getting antsy about on-device debugging with SDK 3.0, which as most of us know broke our preferred method. It looks like the only answer may be to use an outdated version of the SDK, but I'm going to look into it asap. My plan was to use an external drive to install a throw-away virgin copy of OSX. That way, I can experiment and play, and just trash things that don't work so that I know EXACTLY how to install properly. Incidentally, I also need to use this setup for a few similar things at work. The problem is that my MBP's DVD burner is a piece of crud. I say that conclusively because everyone else with a Macbook Pro has the same problems after some time. At this point, it still READS DVDs (mostly) but it can't burn to save its life. My OS disks got horribly marred by someone I loaned them to, and while I had backup images on an external drive, they're clearly not helpful if I can't burn disks 
. Today though, I'll have access to fresh, OEM disks, so I'll get my install going, image it with SuperDuper or Disk Utility, and that should be the ticket. I'll keep you updated, but I expect that I might be able to start working on this after work tonight or tomorrow sometime. In the mean time, the best resource on this problem (and the one that I plan to use to get some procedures going) is http://iphonesdkdev.blogspot.com/.
iPhone OS 3.0 Gold Masters Relased
Get them while they're hot! http://www.iphone3g-mods.com/ (coral) has a great list of download links for all the various hardware versions. There are a couple of notes: First, this is intended for developers only. As such, these FW versions lock your phone into "testing mode," meaning you can't then downgrade to an old version. Also, this final pre-release is not jailbroken (rather, it probably is, but the JB is as of yet unreleased). So don't plan to use this on your main device if, like me, you rely on your jailbreak. I'll probably only install this on my iTouch 1G, and wait for a proper jailbreak following the official release.