Scribd, a popular site where people can share and sell written content, is unveiling its grand strategy for mobile devices today, one that definitely goes beyond just releasing an iPhone application.

“There’s a lot of great competition in the [e-reading] market,” said co-founder and chief executive Trip Adler. “But rather than try to build our own device, we’re just going to try to be on all devices.”

Adler told me that there are three main components to the San Francisco company’s strategy. The first, which goes live today, is the ability to send documents to a number of devices. So if you’re reading an e-book that you like, you can send it to your phone to continue reading on your way to work (uh, assuming you take the train). Or if you’ve created an important PowerPoint presentation, you can send it to your Kindle device to either review before a big meeting or to show to others.

The send-to-device feature should work on e-readers like Amazon’s Kindle, the Sony Reader, and Barnes & Noble’s Nook, as well as Android, iPhone, BlackBerry, Palm, and Windows Mobile phones. Scribd sent a sample e-book to my iPhone, which basically took the form of a text message with a link. When I clicked on the link, it brought up a part of the Scribd site where I could view the book as a PDF. Although the iPhone doesn’t support Flash, the technology Scribd uses for its existing document viewer, the book still looked good, with smooth scrolling and high image quality.

For now, this feature is limited to free content without DRM-sharing restrictions, but Scribd said that over time, it will expand the documents covered.

Another part of the strategy, also live today, is the Scribd Open content Platform for E-Readers and mobile Devices (SOPED). Adler said SOPED is basically a set of APIs allowing device manufacturers to integrate Scribd more closely with their e-readers, for example by adding a “Search Scribd” button that lets users browse and search the site.

And, yes, there will be an iPhone and an Android app — they’re planned for next month. Adler said that while the “send to device” feature is about making something you’re reading accessible even when you’re away from your computer, the apps are about allowing users to actually browse Scribd content. Eventually, Adler said, Scribd will integrate the “send to device” and app experience.