Here is a list of things you can do to help prevent receiving spam in the first place:

• Do not use a catchall email account on your domain(s). Only list aliases and POP accounts that you actually use. This stops the frequent spams that fire off emails to a list of names on a domain.
• Obfuscate your email addresses on your website, i.e. replace them with Java Script "trick" email addresses, or, switch to web forms for initial contact, rather than displaying an email address.
• Never, ever, click on any links in any spam - especially not to "unsubscribe". All this does is confirm to the spammer that they have a "live" address.
• Configure your client to read any incoming emails in plain-text, never html. Html spam emails contain links to graphics and scripts on spammers sites, confirming your email address.
• If you are using Outlook XP or 2003 you can disable viewing in html, instructions are given here: Outlook Tips
• In your cPanel, use :fail: in your default address to prevent any unsolicited email being delivered to your default email address.