Reports are coming in that Twitter for BlackBerry is having issues logging in. I noticed mine stopped working yesterday I thought it was due to the new OS I installed but others are saying they have not upgraded their OS and have the same issue.
The BlackBerry twitter client has ways to go compared to 3rd party clients like ÜberTwitter and SocialScope. So I am hopping that the issue is due to RIM getting ready for a new release.
Let us know if you are running into issues! Thanks Julian for the tip!