Evidently there are a couple of different versions of this same file name. One can be a trojan/keylogger type and one is the program associated with yahoo messenger that runs at startup (you can turn it off supposedly in MSCONFIG/Startup tab) and notifies you when somebody else in yahoo is trying to reach you.

Here's one link that describes some problems with it:

http://www.neuber.com/taskmanager/process/ypager.exe.html

And another link from google giving other links so you can read about it and decide what you should do (uninstall/disable it) or leave it alone.

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rls=GGLD,GGLD:2004-21,GGLD:en&q=ypager

TONI