Another must installed software on Windows Mobile that I forgot to mention ~ Microsoft SQL Server Compact 3.5 Service Pack 1. You won’t need it like Microsoft .NET Compact Framework 3.5 but some applications do require it to be installed. After playing HTC HD2 for 4 months, I just need it now.
You can download Microsoft SQL Server Compact 3.5 SP1 at Microsoft website at 22.0 MB. But you need to copy to your desktop PC first before install it at your Windows Mobile device. That is slow. Therefore, I have Microsoft SQL Server Compact 3.5 SP1 Cab for you all. There are 2 files in the zip ~ sqlce.ppc.wce5.armv4i.CAB and sqlce.repl.ppc.wce5.armv4i.CAB. Install both of them.
Download Microsoft SQL Server Compact 3.5 SP1 cab here.