What exactly do you mean by "foreclosures?"
Are you looking for property that has already been foreclosed and is not bank owned or are you looking for property that is in the PRE-foreclosure arena where the homeowner still owns it but is in about to lose the property?
For REO's (bank owned), all you need to do is search the MLS. But the investor should already have an agent doing that, so I don't know what you could contribute.
For the Pre-for's, there a several options, including the courthouse. You cold-call, door-knock, post flyers, business cards, signs, etc.
Biggest question is if you are birddogging for this investor, then why isn't he telling you what to do and what to look for? That is the whole point of a birddog. The investor should "train" them to find the type of properties that they want. A hunter doesn't get a dog, take them into the woods and say, "SHOW ME THE BIRDS!!!!" They train them first, then go hunting.
Raj