According to this site:
http://www.liutilities.com/products/...brary/svchost/
svchost is described as:
Process File: svchost or svchost.exe
Process Name: Service Host Process
Description: Application that works as a host process for services that run from dynamic link libraries.
Company: Microsoft Corp.
System Process: Yes
Security Risk ( Virus/Trojan/Worm/Adware/Spyware ): No
Common Errors: N/A
Basically, it's running when you're running a program that runs a .dll, which is why there's several there.
