Here's what i do.
1. Install git on machine . In my case it is linux.
2. Sign up and create repositories on github and gitorious.
3. Add remote repositories with different names for both repos.
4. Commit and push.
Follow this workflow if you want.
git init
touch README.md
git remote add origin http://github.com/var/git/myapp.git
git remote add hosted http://gitorious.com/var/git/myapp.git
git add .
git commit -m "update"
git push origin master
git push hosted master
That's it. You are now pushing and hosting the code on two different repositories. You can add more repositories with different names into this and follow the same steps.