I created a repository for hosting a blog on github.Is there any way that I can create more to host multiple blogs?Am I limited to just one repository for hosting(since username.github.com can only be used once?)
You can have one site per GitHub repository. Repositories other than "username.github.io" will be published at http://username.github.io/REPONAME. Those repositories will publish whatever you push to the "gh-pages" branch.
A better description is available in the GitHub Pages documentation.
(since April 2013, all
username.github.com are now