I Tweet from my desktop,
I Tweet from my phone,
I Tweet at work,
I Tweet at home.
(sounds like a line from Dr. Seuss)
On my phone I normally use the mobile client page or plain old sms.
Recently Steve Clayton put out his wishlist for Twitter and he asks for a rock solid Windows Mobile client.
Well Steve, have a look at Tiny Twitter
But don't just take my word for it - even Jeremy "OffBeatMammal" Cath loves it and you will too.