Well it seems like the long awaited Firefox Mobile browser named Fennec will be releasing on the Windows Mobile system soon. Below is an update from the Mozilla Wiki site for the browser:

We are targeting a Milestone release for the first week of February, targeting the HTC touch pro.

We are two patches away from the meta goal of building from trunk. The tools changes have review from dougt, and are waiting for review from ted, who has promised review by the end of the week. NSPR changes are waiting for review from Nelson, who asked for and received a patch against NSPR trunk

For more info head over to the Wiki.