How Google counts back links?

I went to Yahoo Site Explorer and used SEO Quake Tool bar, discovered that my site has about 1,000 back links and half of them are from legit hight PR sites. But when i looked at G. back links stat on SEO Quake Tool bar or searched Google with link: command i found only 3 back links, very crappy back links too. Anybody knows what is going on here? Whey Google hides all the good links i have? Thanks

I am not sure 100%, but I think that generally google, index and show this links slowly, and in any case show only do follow backlinks.

So now when I check backlinks from my competitors, I try to get first the backlinks showed in google.

Hope may help