WinPwn 2.0
Support for both 1.1.4 and 2.0
Custom Image Support
Custom Payload Support
3g iPhone support
Bugs

Some users have had problems with installing Cydia on Windows XP. This will be fixed in tomorrow's release.

2.0 How to:
First create a custom IPSW using the IPSW Builder.
Click "Ipwner" and browse for the custom IPSW that you just created. This will pwn itunes and allow you to flash custom IPSW files via DFU mode
Once you have pwned Itunes, put your phone into DFU mode. If you don't know how to do this click here.
Once you are in DFU mode Itunes will pop up and then you can hold shift and click restore and browse to your custom IPSW file.
Done!