I think what the parent commenter meant by showing your work is to have either a list of related projects you've finished and details on how they relate or all the material you've gathered so far and a very specific question regarding your current stumbling block.
If you approach a guru (or anyone, for that matter) with a question that would only take five minutes to google, of course you'll get the shaft. On technical issues, everyone is guilty of ignorance until proven innocent, and willful ignorance is not lightly tolerated.
Lots of folks just aren't looking for mentorship opportunities, too. I'd say scan the list of current and previous mentors for something like Google's "summer of code" and use it as a jumping off point for contacts that have a track record of providing mentoring to aspirant hackers.
I'm guessing I'm not alone in being tired of the whole "Oh, you can code? I have an idea for this site.." thing. Gotta pitch it right to people overwhelmed with that sort of thing. If you really just want a few words of feedback so you can go out there and find a techie to work with knowing it's technically viable, that's great, but that's not necessarily what I'm picking up from you here.