Sharpcast said today it’s offering a free version of its SugarSync service, which we found to be the easiest for synchronizing data across any of our digital devices.

The San Mateo, Calif., company said users can now sign up for a free account to back up, access, and share files, documents and music across laptops, desktops and mobile devices. The company has also revised its user interface to simplify set up. Free backup apps are available for the BlackBerry, iPhone, iPod Touch and Windows Mobile devices.

You can also stream your home music collection on any web browser or iPhone and directly upload and sync photos from your mobile phone. This kind of service fits right in with the digital lifestyle of consumers who are collecting more and more precious digital stuff, like family photos. SugarSync also lets you share your folders or files with anyone you choose.

The company was founded in 2004 and has 30 U.S. employees and 18 overseas contractors. Competitors include Dropbox, Apple’s Mobile Me and Syncplicity. SugarSync says it’s more flexible than Dropbox, since users can share any folders across multiple computers without putting the shared items in a special folder. Users can also share data to cloud-based storage, while not sharing those same items with other computers. That’s useful for devices such as netbooks, which are smaller than laptops and have limited hard drive or flash memory space.

Mobile Me isn’t available on as many platforms as SugarSync, has limited storage space, and doesn’t synch files immediately in real time. Syncplicity is another rival, but that solution isn’t yet available on as many mobile platforms. Sharpcast has raised three rounds of funding totaling $26.5 million since 2005. Investors include Selby Venture Partners, Draper Fisher Jurvetson, and Sigma Partners. The most recent round was a $10 million round in January.