In regards to your question, you can use Yahoo! Site Explorer to see how many backlinks a certain site has. But as others said, it doesn't just depend on the number of backlinks, but also the quality, relevance, and content.
I use SEO Elite to do this. It shows you the backlinks up to a 1000 and it shows you what anchor text their using and if they are linking back or not. It show unique ip's and the age of websites and also whois info. Hope it helps
just keep building back links organically. The problems start when you try to be too clever and cheat the system