Twittpages.com : Trademark Infringement?

Is the twittpages.com domain name infringing the trademark of Twitter.com?

I would not use it. This article discusses Twitter's policy on trademarks. They generally allow "tweet" in products, that use the Twitter API. They have trademarked "tweet" but unless you are doing something wrong (scams, copying twitter interface, etc) they will let you be:

"We have applied to trademark Tweet
because it is clearly attached to
Twitter from a brand perspective but
we have no intention of "going after"
the wonderful applications and
services that use the word in their
name when associated with Twitter. In
fact, we encourage the use of the
word Tweet."

And they will probably send a "Cease and Desist" if the site has "Twitter" in its name. As for "Twit", it is trademarked by twit.tv.

So either way with "twitt" you are going to be infringing on some trademark.

Then, there is this convention that twitter related services use "Tweet", so even if Twitter are ok with you using "twitt", there is already a site called tweetpages.com, so you might lose a fair amount of traffic when people confuse the two.

Bonus definition:

twit: n. a stupid person. (Also a term
of address.) : What a yuppie twit!

Extra reading:
link,link,link,link

IANAL, but that would be up to Twitter to decide if they want to pursue it.

It would also depend on if you are competing with them.

I don't believe it would be, but, you could just check with their general counsel and see how they would react, perhaps.