is it possible, via the web interface or the API, to look for an specific link into Google's Cache?

You can use the Google API to get the cache for any page, yes. Is that what you mean?

Download the "google toolbar"

The tool allow you look up any url/word.
Not only you get the PR, Backlink's, revieled
but will also be able to check if/how the site appear's in Google cache. ....

Regard's :O)

can i cache google page...?