I have just found out that the name of the artist who sang it in the movie is Howard Huntsberry.
Here's a useful tool for this kind of thing.
It is basically a database with playlists for just about any album imagineable.
This is the listing for the Ghostbusters II soundtrack (Why would anyone buy it in the first place??)
But do yourself a favour and get Jimmy Barnes' version of the song......it is on Napster.