Today, IMVU, the avatar-based social network and virtual world with over 35 million users, announced a  new partnership with Offerpal Media, a provider of monetization and advertising for social networks and virtual worlds, Now. IMVU will offer a new way for players to earn free virtual currency through the use of Offerpal’s targeted offers, trials, and surveys.

In five and a half months or so since receiving $10 million in funding in a round led by Best Buy Capital, IMVU has grown by nearly 20% from the 30 million registered users reported at the end of January. At the time, the company said that it was generating around $1 million in revenue each month, a number it hopes to increase.

“We implemented Offerpal to further monetize our user base,” says Kevin Dasch, IMVU’s Vice Preseident of Finance and Business Development. “This platform provides yet another way for our loyal members to obtain IMVU credits, our virtual currency.”

IMVU users can use the world’s virtual currency to purchase over 2 million items (developed by over 100,000 developers) from IMVU’s digital goods catalog including clothing for avatars, props and furniture for rooms, and other premium services within the 3D world.

As social games and virtual worlds mature, developers are increasingly turning to “managed offer networks” like those from Offerpal, Super Rewards, Sometrics, Gambit, and Peanut Labs Media to assist with virtual currency monetization. Many developers are doing quite well as the space continues to expand rapidly in 2009.