Cactus Language
Cactus Language.com is a site that offers worldwide courses in up to 31 languages that range from Arabic to Yiddish.
It is a well laid out site which makes it easy to find a course in your area.
Interestingly they also offer holiday learning courses. Providing accommodation in the city you wish to learn your new language in. So if you need a break and want to learn a new language while you are there, this is the site for you!