So I updated weather icon in Cydia, and my iPhone ended up endlessly respringing to a point where nothing can be done. (3.1.3, iPhone3GS New Bootrom, 32GB)

-Endless Rebooting/Apple Logo with Respring

My easy fix:
(You must have openssh installed in cydia before this happened)

1) Plug in your phone to your PC.
2) Run WinSCP and log in, even though you are stuck on the apple logo.
3) If the log in works, quickly click on the Terminal (Ctrl-T) button, and type 'dpkg -r com.ashman.weathericon' (No quotations)
4) Phone should turn on normally.

If the log in doesn't work, you might have to DFU and restore.

Note to Stimpy: Please thoroughly test your jailbreak apps before releasing updates. We love em, but we don't love restoring our phone.
I hope this helps anyone.