I see some domain names have "icanhaz" in them. I think there must be some story behind it. Do you guys know?
I'm sure there is a good history, as it were, of the lolcats thing. "I can haz..." is something that the cats in these pictures often say.
As to the strange grammar, that's the point, that kittens aren't particularly educated yet in English (yet?) and so have terrible grammar (they can't read very well either).
It's one of a long line of "memes" emanating from 4chan (Along with lolcat, rickroll, etc.) It came from a picture of a cat with the caption "I CAN HAS CHEEZBURGER?" and since then the "I can has" part has been applied elsewhere.
Basically it's an internet in-joke which became adopted by people who were not "in" with the joke.
See: [Link removed - see comments]
WARNING: The above website may contain objectionable material and is generally considered NSFW. It is certainly not a reputable source of information, however it is the usuall go-to for background on such internet-originated phenomena.