Facebook is stretching their limits of their social reach beyond the web, and onto your iphone. Now, custom apps can be facebook aware, and allow for iphone owners to log-in to facebook, leveraging the facebook connect service.

For those of you who are not familiar with facebook connect, the original offering was web based only; conceived sometime last year and it allowed any web site to have some user integration with facebook, while allowing access to it's social features via it's API and proprietary markup language. Now with an iPhone offering, it gives the user more reason to stay on the very popular social networking site -- even without being on the social networking site.

More information about facebook connect here.

If you are interested in developing iPhone applications leveraging facebook connect, here is the link to their starter kit. Documentation link is here.

Read the original announcement on their developer blog.