http://www.wiforums.net/

How many browse UA from their cell phones? This is an inexpensive program that converts the forum for mobile viewing. And its pretty inexpensive too! A car forum I'm on just installed it.

Features:
The ability to reply to topics
Centralized and customizable language system
Wireless posts contain the words "Wirelessly Posted" and the user-agent/browser type of the phone/handheld that it was posted from (visible on your web based forum)
Email Notifications
Enforced posting intervals help reduce the possibility of unintentional 'double posts'
User Authentication (using the same usernames and passwords from your web based forum)
Easily grant, or deny specific users/usergroups or all users, access to your wireless forum via "WiAccess", the web based control panel
"Log in Once" cookie support.
My Prefs: A user specific control panel that allows your users to do the following:

- Enable or disable external image support (JPEGs, GIFs, PNGs, color smilies etc..)

- Enable or disable the truncation feature

- Control how many topics and/or posts are displayed on a single page

- Specify the the name of their cellular phone, PDA, or other WAP enabled device, and it will be appended to the "Wirelessly Posted" line.
The ability to read truncated posts in their entirety. A link labeled "[More]" will be displayed below posts which have been truncated.
Can be offered to your forum members as a subscription based service.
Owned License (no royalty fees), with 1 year of technical support and product updates