By Rieva Lesonsky

Are you a sole proprietor, freelancer or independent contractor looking for new sources of income? just released its second-quarter Online Employment Report, showing that rates for independent contractors hired via Elance have risen 45 compared to last year.

Online professionals earned over $23 million in the second quarter of 2010 on Elance, and more than 112,000 businesses hired online workers at the site.

“Frustrated by the traditional on-site staffing model, businesses are embracing virtual and hybrid work structures which allow them to tap into highly skilled online teams on a flexible basis,” says Ellen Pack, vice president of marketing at Elance.

What skills are in particular demand? According to the Elance Online Employment Report, the job categories experiencing the fastest growth online include marketing, IT and creative services, while the hottest skills include cloud computing, mobile and online marketing.

While IT continued to be the number one job category, marketing showed the largest growth in earnings year over year (73 percent). SEO, Internet marketing and lead generation retained their positions as the skills most in demand within marketing. Business interest in using social media marketing channels continued to grow, moving social media marketing into the No. 4 spot, while e-mail marketing moved up one notch to the No. 7 position.

The IT category remains the top performing job category with a 44 percent increase in earnings in Q2 year-over-year. Fueling this growth are companies embracing cloud computing platforms and mobile devices that need highly skilled work teams. Google App Engine, the cloud-based application development platform, showed the single largest increase in demand.