We've written before about Viadeo, a business-oriented social network. Today they announced opening up their API and to get folks interested, they are starting a contest for the best app developed on their platform. The contest will run until October 14, and the top winner will receive 10 large plus a year of free service on their site.

"By tapping into Viadeo's social graph, third party developers can create more compelling applications--opening up new markets and delivering enhanced business capabilities. Some examples of applications that can be socially enhanced are collaborative workspace tools, CRM, email clients and social aggregators to name a few," according to the announcement. There are lots of examples on Viadeo's developer site.

Submissions will be reviewed by the judging panel from October 15-20 with the winners announced on October 24.