One of my favourite polyglots on the internet is Jennifer from www.ielanguages.com. She’s probably not much older than me, so reading about her is like seeing what I might have been aiming toward if I had concentrated more on languages while at university, instead of getting quite so carried away with literature, cultural studies and philosophy (but that is a story about not-knowing-at-the-tender-age-of-18-exactly-what-you-want-to-do-with-your-life, and perhaps I will share more on that another time).
On her website, she provides language tutorials of varying lengths (depending on the extent of her knowledge in the given language) of Indo-European languages. There are also tutorials written by other people for languages she has not studied.
These tutorials are nicely structured, from the basics up, providing vocabulary and grammar (with example sentences) at appropriate intervals, as you would learn it in a class. They provide phonetic spelling and, in some cases, audio files. There are also excercises to practice what you have learned.
All round, this is a very good resource. That being said, I should add that I have never tried to learn a language completely from scratch from one of her tutorials; however, I have used them for revision and as an additional learning resource.
Beyond the tutorials, there are other points of interest on this website, like her linguistics introduction, and lots of info about France and French – she lives in France.