As a registered user of PocketMind's PocketMusic Bundle, I received an e-mail this afternoon notifying me that the product was newly updated.
If you previously purchased PocketMusic Bundle, the update to version 4.0 is free.
There is also an updated freeware version.
These updates supposedly add support for Windows Mobile 5.0 devices.
I haven't installed it yet, but will be doing so very shortly.
For details, see
http://www.pocketmind.com/news.htm