What is it?
Possibly One of Symantecs top threats currently - W32.Mydoom.M@mm - Java.exe

What does it do?
W32.Mydoom.M@mm is a mass-mailing worm that drops and executes a backdoor, detected as Backdoor.Zincite.A , that listens on TCP port 1034. The worm uses its own SMTP engine to send itself to email addresses it finds on the infected computer.

Removal:
Symantec has the full dirt ( Here )