Nokia has jumped on the social networking bandwagon with a developer release of Mosh, a new site that lets mobile users connect with one another and share content regardless of their device or network.

While built from the ground up for mobile use, users can access Mosh by both mobile phone or desktop Web browser. Web access allows Mosh users to upload larger files (such as MP3s) without ringing up big data charges.

In Nokia’s own words, taken from its sparse, invitation-only sign-up site, Mosh is “a user-generated content platform designed specifically for use with any mobile device. Create, upload, collect and share applications (like games, software mashups, videos, blogs, music and photos) all from your mobile.”

In addition to sharing content, users can also browse user profiles and make contact with one another via the service. Those capabilities clearly place it in competition with mainstream social networks such as Facebook or MySpace, with its differentiating factor its mobile-first design.

Developers were invited last week to test out Mosh on the Forum Nokia site Web site (the posting includes a password to access the beta site).

“Mosh is a grand experiment for us: a platform that puts unprecedented power in the hands of mobile users,” wrote Lee Epting, Vice President of Forum Nokia, in a letter to developers announcing the beta program. “Regardless of your mobile device’s manufacturer or make, Mosh enables you to create, collect and share your content and applications in a community setting.”

According to Epting’s note, Nokia will be adding tools and other new capabilities this fall to allow Mosh users to more easily create and share content via the site. The free site can be accessed via mobile phone using any WAP browser or using downloadable software that can run on Nokia S60 or Series 40 devices.

Users can register for access to Mosh via the Web at mosh.nokia.com or from the mobile phone at mosh.nokia.mobi.

Mosh sounds similar to services available from Twango, a company Nokia acquired late last month Twango, a Seattle-based startup led by former Microsoft employees, lets users store and share photos, videos, and other media and access from their PCs or mobile phones.

In an FAQ posted at the time of the acquisition, Twango said its service would continue to run uninterrupted under the Twango.com, with more details coming from Twango and Nokia in “early 2008.”

Nokia also runs a mobile service dubbed LifeBlog, which lets users write blog posts and upload pictures via their cell phones.

You can see some pictures (including the one above) of both the Web interface and mobile interfaces of Mosh at the Nokia N95 Blog. You can also see the site in action via a “screencast” demo.