Check out Conversation Exchange!

http://www.conversationexchange.com - you create an account and then search for practice partners. You can search by various criteria such as gender, age, nationality, hobbies. You can search for pen pals, audio chat partners, or video chat partners. You can use their internal messaging service if you don't want to give out your email address.

Also check out iTalki, weSpeke, Busuu, and goSpeaky.

Hi, I'm also learning French. Would you like to practise with me?

I'm interested in a French speaking pen friend, I am currently studying french at school :)