[matthew-wegner]

Just did this on an iPhone 4 running iOS 4.0.1. Worked like a charm! Some of the Cydia repositories are being hit hard and may time out the first time you load Cydia (BigBoss especially).

Edit: MyWi's USB tethering works, looks like Wifi tethering does not.

[sev]

Tried wifi tethering and it worked. Although at first it didn't...so I went into settings changed some settings around and then back to how they were at first and hit 'done' and it worked. Sorry for the non-technical explanation but that worked for me.