First off, if you don't know what Zero no Tsukaima is, watch it. Now.
I have done my best to include no spoilers in my post, if you haven't watched/read this series, and you don't want to know what happens, I suggest you don't read any posts beyond this first post.
It's NSFW in some places, but it's still a very good series.
It began as a series of light novels in Japan, and the official translation is being done by Seven Seas Entertainment.
There is also a manga, and anime series. I've only read the first 2-3 chapters in the manga, but it seems to be more fan service than anything else.
The unofficial translation of the light novels is being done by Baka-Tsuki Projects who are collaborating with a few other groups. The light novels do contain fan service, but only in the lightest sense of the word. The light novels are actually quite mature for their genre, and the characters being 17+, you'll see why I only use fan service lightly. The novels were written very well and I recommend them. I myself will buy them as Seven Seas comes out with them.
The anime has two seasons out. The anime is a cross between the light novels and the manga. Having watched both of these seasons (and having one downloaded to my laptop) I can safely say that, while not as true to the novels as it should be, it's still worth watching. The first season was excellent, it really got you into the series as a whole, but the second season wasn't as good. I cried during Season II's finale, but got really annoyed later. (You'll see why if you watch it.) Most of the fans (including myself) are crying out for a third season due to unresolved plot, and we want more Saito + Louise, but we don't know if they plan to do the third season, or if this is it. If there is a third season, it is expected to air sometime this summer (hopefully).
Discuss.