From a command prompt, type "tasklist /svc" to see a list of services running. Peruse the list, and the items shown against "svchost.exe" will indicate what each instance of svchost is responsible for. In my case, the items include the dns cache service, dhcp, secure logon and the crypto service for my drive. So I'm not inclined to stop svchost. Your mileage may vary. (XP Home doesn't support the command. XP Pro and others do.)
If anything in the list particularly interests you, note the PID number and enter Tasklist /FI "PID eq xxxx", where xxxx is that number.
There are a few other commands you can play with.
In general, I don't remove random parts of my auto because I don't perceive a use for them or understand their function, and I apply the same logic to my computer.