I'll be using Debian as the example distribution for this.
Setting up a webserver in Debian (or, for that matter, any distribution) is relatively easy. [url=http://allyourtech.com/content/articles/16_01_2006_setting_up_a_local_web_server_in_debian_linux.php][b]Here's a Debian webserver howto.[/b][/url]
I've never seen a Linux distribution that doesn't include a Mail Transfer Agent (MTA) in even the minimal install. An MTA is the software that is used to run a mail server. For instance, the default MTA for Debian is called Exim. By configuring this during the operating system install, you can set up a mail server. That process is kinda self-explanatory during the OS installation, though you may have to use Google to help out for special configuration options.
In addition, this link is for an article on [url=http://www.linuxdevcenter.com/pub/a/linux/2003/09/25/advanced_mail_server.html][b]setting up an "advanced" email server using the Debian distribution of Linux[/b][/url].
Some more information about Debian -- specifically relating to [url=http://articles.techrepublic.com.com/5100-10877-6105410.html][b]installing Deiban[/b][/url] and [url=http://articles.techrepublic.com.com/5100-10877-6104158.html][b]using APT[/b][/url], Debian's package management system -- is available right here on TechRepublic.
You might also be interested in learning how to use the basic help system of Linux and other unices, [url=http://articles.techrepublic.com.com/5100-10877-6102898.html][b]the manpage system[/b][/url] (also known as the man, or manual, system).
Let me know if you need more information.