Any Stamp Collectors??

[travlnz28]

Here's the deal. My step father passed away recently and he used to be a big time stamp collector. I'm talking probably a million stamps with some dating back to the 1800's. They are from all over the world and most are cataloged by country. My mother has no use for them now and we'd like to get an idea on value. I know this is a bit vague but if anybody knows something about stamps, please give me a clue to how I might get an idea on the value. It would have been great if he would have been into muscle cars instead!