Detect malicious URL destination?

Is there an online service that can tell me if the file at a given URL is malicious?

I'm publishing URLs in my website, and would like to warn users which URLs could contain malware. I'd like to request a report with an HTTP request like:

http://www.somemalwareadvisor.com/canitrust?url=...

Thanks!

From stackoverflow cronocr

• This seems like a cool project that you might be able to hook into: linky

  From Chuck Vose

• You might be able to pull some data from WOT:

  http://www.mywot.com/en/scorecard/example.com

  From Computerish

• http://code.google.com/apis/safebrowsing/developers_guide_v2.html

  : Google chrome uses this as a pre-filter before going to a new site. It's very detailed, I love this thing. It's probably saved millions of people from drive-by-downloads and XXS.

  cronocr : I checked the API and it's not exactly what I'm looking for, I need a simplier method. But I was trying to access twocows.com and got a warning from Safe Browsing. I requested more details and got this URL: http://safebrowsing.clients.google.com/safebrowsing/diagnostic?client=Firefox&hl=en-US&site=http://twocows.com/ This is simple enough to get information for a page, and I can both present the information to the user and parse to give automated warnings. So this would be the best answer to my question.
  From Wrikken