Of course you can.
Mandrake should have installed everything you need. In the mandrake control center (assuming you'll want the convenience of a GUI to configue your system), you can set every service that's started at boot. Apache is the way to go for a web server. I'm not too clear on exactly what's installed as an ftp server, but it's there. Samba will make a nice file server and... well... there's SOMETHING in there for a print server.
Run through the configs in the control center (there's a nifty little info button in there if you're not sure what something is) and set everything you want to start at boot, then reset the machine. Voila, we're in business.
Now, configuring apache. Hit your computer's IP address and you should see the default apache page now. To set up your own page, you're going to either replace the default files or point apache to a custom directory. Either way, go edit /etc/httpd/conf/httpd.conf. You can see the default directory here and either replace those files or point this somewhere else. Be sure to redirect the script aliases if you're planning on running scripts from this new directory. You can also set up virtual hosts and whatnot here. Very nice.
The ftp server should just do it's thing. It'll draw a user list from Linux's user list, so you're all set.
And here I must stop, for I am winded. Anyone else for samba and a print server?