LinkedIn, a popular professional social network, on Monday launched a mobile version of its Web site, which is now accessible to more than 19 million members.

Professionals worldwide use LinkedIn to create trusted networks with colleagues and other professionals, and to share expertise, business contacts, and job opportunities. LinkedIn is backed by several investors, such as Sequoia Capital, Greylock, the European Founders Fund, and Bessemer Venture Partners.

As part of a beta release, LinkedIn this week became available on various Web-enabled mobile devices, allowing members to search profiles with photos and bios, make introductions, invite people to join a network, and receive updates while on the go, said LinkedIn.

"Let's face it, every professional today is carrying a wireless device. Many of these professionals are on the move, attending conferences, sales meetings, and client events. Making LinkedIn available on mobile devices responds to both these business realities and will be great for our users," said CEO Dan Nye, in a statement.

LinkedIn has optimized its Web site specifically for mobile devices and members can log into the mobile application at m.linkedin.com. The beta version supports different languages, including English, French, German, Spanish, Japanese, and Chinese. The final version will become available this spring, according to the company.

LinkedIn isn't the first social network to go mobile. It follows in the footsteps of many others -- such as MySpace and Facebook -- that are using mobile phones as another channel to reach large audiences.

In December, for example, social-network site MySpace said Sprint will become the first U.S. wireless carrier to offer charge-free access to MySpace Mobile. Sprint subscribers with data will be able to access MySpace Mobile plans through the carrier's portal. It will feature a rich graphical design and an improved e-mail interface, among other features.