You can find our more about Facebook Mobile via: www.facebook.com/mobile/
Facebook currently provides the following Mobile access methods:
- Downloadable Facebook App (varies by platform)
- m.facebook.com for Basic Mobile Phones
- touch.facebook.com for Touchscreen Smartphones & Mobile Phones
You can read the full Facebook announcement on their blog found here: http://blog.facebook.com/blog.php?post=297879717130.