Today DevTeam released an ultrasn0w update that fixes a bug for those who run it on firmware 3.1 and 3.1.2 with the 04.26 baseband. This bug was about a missing carrier name in the upper left-hand corner of your home screen. The update is avaliable in Cydia (repository http://repo666.ultrasn0w.com).

We remind you, that ultrasn0w 0.92 doesn’t work with baseband 05.11.07!

[Update]: if your 3G or EDGE connection isn’t working try manually clearing and re-entering your APN.

[Update 2]: Carrier logo fix confirmed (by order of tweet):
USA, Thailand, Austria, Trinidad, Germany, China, Kuwait, Serbia, Poland, France, Nigeria, Egypt, Pakistan, Ireland, UK, Turkey, Sweden, Switzerland, Malaysia, Hungary,The Netherlands, Bahamas, Jamaica, India,
Israel, Belgium, Canada, Portugal, Denmark, Costa Rica, Italy, Chile, Argentina, Brazil, Japan, Mexico, Venezuela, UAE.