You could try NTP.
http://www.codeproject.com/csharp/ntpclient.asp

Signature
Tim Wilson
.Net Compact Framework MVP
<Feedback>
Do have an opinion on the effectiveness of Microsoft Windows Mobile and
Embedded newsgroups? Let us know!
https://www.windowsembeddedeval.com/community/newsgroups
</Feedback>
> My computer seems to loose seconds from day to day so I would like to have
> my app download the official time and set my computer's clock. What's the
> best way to do this? Is there an official time website that offers a library
> for getting the time? Any thoughts?
>
> Steve