Remote desktop clients for Windows Mobile.
If you want to check out clients for a different OS, go back to the Remote Desktop Clients index.
If you're looking for servers, go to the Remote Desktop Servers index.
Some Windows Mobile phones come with a Remote Desktop client, but many are deployed without the RDP client. Fortunately, some smart people over at pdaphonehome were able to extract the Windows Mobile 6 RDP client into an installer that works on WM5 and WM6. You can find it on their forums:Windows Mobile 5/6 Remote Desktop Client