What is it?
Intergrated Search Technologies - istsvc.exe
What does it do?
istsvc.exe is spyware at its most annoying - on any infected system, it will monitor browsing habbits and send the information back to base, which is analysed for marketing purposes. This process will also display popup adverts on your system, probably targeted based on your browsing habbits where possible. It should be removed without hesitation.
Most popular spyware removal programs will get rid of this, such as HijackThis.