[hashbury]

All my sites are regular sites, no "mobile sites"
Most of my signups come from iphones, blackberrys, and ipods, but i do get a few signups from comps here and there.
My best traffic producing method is by using a main blog to feed a bunch of little niche blogs on there own domains.
Various tgps (such as the hun) are starting to accecpt mp4 formats.
I have also seen very good results from webmasters using mobile link directories where everyone submits their mobile sites.
To get started in mobile i would suggest targeting a device that can display regular html.
I go after psp, iphone, ipod, and blackberry. Although some older blackberrys seem to have problems with sign up forms.
You should have mobile traffic going to your sites right now, just check your stats. Having one link to a mobile porn site on all your sites can turn those users into sales.
I do have a little bit of inside know how in mobile, and i will tell you our biggest sellers are blogs (I will actually be introducing some hosted iphone rss feeds for my company soon).
One other thing, The mobile market isnt over populated with webmasters, So it is easier to make sales and get ranked for good mobile keywords.
If you have any more questions or need any help, Just Let Me Know.