The Microsoft MSDN Backstage at MED blog IDs the…
Top 5 Windows Mobile Twitter Apps
Actually, as the blog admits, these are the only five Twitter apps (plus a homescreen plugin) for WiMo they know of (me too for that matter). The apps are:
1. TinyTwitter
2. Pocketwit
3. Twobile
4. CETwit
5. Twitula
…and the home screen plugin
– Twit Today