The Dev-Team has updated redsn0w to version 0.9.6beta5 for unlockers. Below is all the info.
Update #2: The new redsn0w 0.9.6beta5 is out. It gives both Windows and OSX users the ability to flash the iPad 06.15 baseband on iPhone3G or iPhone3GS. It fetches the baseband files directly from Apple for now (the only IPSW you ever point it at is the stock IPSW for the FW on your iPhone right now). There may be a long delay while it’s doing this (their servers are currently getting pounded).
If you do flash your baseband via redsn0w, please keep it plugged into USB the whole time. You don’t want your battery to die during the flash process!