Facebook released a version of its site for the iPhone today, attempting (like so many others) to capitalize on the success of Apple's sleek new mobile device.Facebook is but one of the many Web 2.0 sites already joining the iPhone, along with Digg, NetVibes, Skype (a third-party version, admittedly) and even an iPhone-dedicated social network called iRovr. Facebook seems happy to join the bandwagon. "The iPhone hasn't even been out for two months yet, but it has already changed the way people think about the mobile Web," the company said in a statement this morning.

The iPhone version of Facebook is a bit slimmed down, lacking the ability to access certain elements like privacy settings and groups from its homepage. It also unfortunately can't access Facebook apps, which have driven much of the buzz around the hype machine that Facebook has become in recent months.

However, there are some substantive additions as well. For one, friends who have listed their phone number on Facebook now get a click-to-call button in their profiles. In my experience, however, it's uncommon for phone numbers to be listed on Facebook, so without more openness by my friends (well, and with my personal lack of an iPhone) this won't become too useful.

Another striking change is the simplicity of the interface and the smooth page changes that scroll the prior Web page off to the left to bring the new one to the fore of the screen. Touching a spot of white space at the page of a friend's "wall," which is basically a virtual message board, allows iPhone users to write a message. Links, buttons and text all get bigger and bulkier, and thus easier to touch.