When I decided my blog had to be bilingual, I started to look for a plugin that would allow me to do it without having to run two parallel blogs. I found several that seemed too complex for a neophyte like myself to implement. Then I found qtranslate and it seemed like it would work. I installed it and have had no problems so far, it works perfectly for me! The only thing I had to deal with was that upon first implementation it messed up all my posts' dates, but after tweaking settings I managed to make it work all right. I only wish that the interface, which is very easy to use for editing posts and categories in several languages, also allowed me to do the same with the site's headline and my profile.
Thanks to the developers!