Is there any code for GPS receiver and for GPS net server available?
I want to build complete application: a client for the MS Win Pocket PDA and a server which shows position of my trucks on map. It is easy to find via internet code for GPS receiver (PDA) but I cannot find corresponding part code for server.
If I am understanding you correctly, you want the code to be able to render trucks on a map on your server.
If that is the case, I think that the approach you need depends on the language you are using. Plotting GPS coordinates on an X-Y plane is not a straight forward thing to do, reason being that if you where to cut the surface of the globe into pieces you would not end up with perfect squares, and would thus have to use a technique called Map Projections.
There are various readily available mechanisms provided by companies such a Google provided that you implement a web application. If on the other hand you where looking for a desktop application, SwingX provides a Java API which allows you to build GPS related desktop applications through the use of OpenStreetMaps.
So basically, you can have something as follows:
Create a concurrent server which accepts data from these PDA's and save it in the DB;
At a given period of time, pull the data from your database and refresh your desktop application or web page.
Edit: You can take a look at this tutorial to see how you can draw and plot on a map Using SwingX. If you shall be using Java, you might want to give a look at this previous SO post for more Java mapping API's.