Mandrake 10.2 will do the job be sure to install Samba and if you want an ftp server take ProFTPd.. easy installation. There's a lot of documentation around on the web, i've learned pretty much anything i know about linux/bsd by the docs and manual.
b) I always recommend Fedora Core (previous RedHat) for beginners. I liked it as a first attempt at Linux. It's easy to install and shouldn't be to hard to set up (there's tons of help on the web, just like for Mandrake). http://fedora.redhat.com/