Thats a good question.
pokerroom.com has a Java client. I miss a few freeplay tourneys now and then I could join if I had a Java capable mobile browser.
I'm getting a new phone from work - HTC s620 - it's not a great phone but its WinMobile 6. Java but no Flash as far I know.
OMAP 850 device. 320x240 screen. Hmmm...... Think I'll have a look at the SDK