Viigo just added a new channel to their app that makes it into a full Twitter client. It also supports Friendfeed, Jaiku, and Identi.ca but those are not as widely used. You can setup multiple Twitter accounts so you always stay in the loop. It is not as intuitive as a full blown Twitter client but it definitely works especially for people like me who are not full time Twitter users.
From the app you can now track multiple channels including live Twitter searches. You can also reply, direct message, ReTweet, mark as favorite, or post your own update. You can see each posters details along with an easy way to follow them from the app.
If you are into Twitter I highly recommend checking this out at www.berryreview.com/viigo if you do not already have the latest version of Viigo installed. I know it works with 3.1.330.
NOTE: To add your account open Viigo and go to the Social Networks Channel and select Add Channel and select Twitter.
Keep up the good work Viigo!