Depending on the kind of mobile site you're developing, there are a variety of online services that let you create & launch your own mobile presence within minutes. They are all good in their own way, and your choice will depend mostly on what you want to achieve.
New local service that lets users create a profile that allows them to upload & share images & videos with other Mostyle members. Publishers can create 3G mobile sites from scratch, based on a set of fairly structured templates. Not a lot of flexibility, but if the templates suit your needs, the sites look great.
Winksite offers lightly less structured site building tools, but still keeps users constrained to a series of modules, with a very list-oriented approach. Plenty of other users' sites to browse.
New beta site that so far offers much flexibility, although still very basic in design aesthetics. Assuming new designs & site measurement tools appear once out of beta, this could be a good option if you need more freedom in site design.
Peperonity is more a mobile social network & news/photo sharing community. You can build your own personal site, use it as a diary or blog & upload photos from your phone. Interesting feature is a Bango account option that lets you add content to your site, then charge others to download it.