It has been designed for teaching so there is a lot of material on their site geared towards learning. As part of that, it has a nice set of tools that make it easy to get started.

There are a lot of books that teach intro to programming in scheme so there is plenty of offline material as well. The little schemer, SICP, How To Design Programs.

See http://docs.racket-lang.org/.

It also has an active mailing list that is quite noob friendly.

EDIT: oh yes, and it is very a 'batteries included' environment. so you can worry about learning the language rather than getting your environment setup.

I also think Racket is a good introduction to Lisp. The documentation is great. Take a look at the vector documentation as an example http://docs.racket-lang.org/reference/vectors.html?q=vector&.... If you are not familiar with the language, there are plenty of examples to help you get going.

I recently started working through The Practice Of Programming and I wanted to compliment it with a functional language. I thought it would make the on ramp to functional languages a little smoother by first coding something in a language I'm familiar with and then port it over (producing more idiomatic scheme is the next iteration). I chose scheme as the compliment and PLT/Racket as the environment. So far, it has been working well.