Why not use Perl?

It has most of the elements of functional programming built-in. I used it to go through the first two chapters of SICP. I started with this page, specifically an article on Perl's implementation of Lambda Calculus, and went from there. The Lambda Calculus is at the heart of functional programming.

There is also an article on using Perl for functional programming over at IBM. After you've read this you'll see (assuming you didn't know of course) that you've done some functional programming before and just didn't know it.

A Google search will find more.

Hope this helps,

Cheers,

John