| | GoogleTalk with Twitterspy
I use GoogleTalk with Twitterspy. Twitterspy isn't something you down load. Basically you get and send your IMs to/through Twitterspy. Basically Twitterspy shows up as one of your IM contacts in Google Talk. It isn't like having a full twitter client but you can send your tweets and subscribe to keywords (like the Twitter track that has been broken for ages). So you subscribe to your twitterusername and if people talk to/about you they will show up on your GoogleTalk. I don't mind this because when mobile the whole twitter stream isn't really necessary to me.
I have more details on how to set this up on my blog:
And if you are looking for a desktop client, get Tweetdeck.