Jean-Yves Perrier has published the plan for prising open the mobile web – evangelism of individual sites and frameworks is a big component, along with spec work and technical changes to Firefox Mobile.
I don’t think I exaggerate when I say that the tasks on that page are some of the highest priority non-coding tasks we have at Mozilla. A WebKit-only web is not much better in the long run than an IE-only web. If you have time to help, please pitch in. Contact Jean-Yves if you aren’t sure where to start.
Particularly if you are someone who doesn’t want Firefox to implement webkit-prefixed properties: working on these tasks is how you can avoid us having to do it, or reduce the amount of it we have to do.