There is nothing worse than having an email box full of spam. In this post I will detail several proven methods to stop spam.
First off don’t let the spam bots find your email address. That means no posting it on your web page, in forums or in your domains whois. Never post your main email in your domain’s whois, always use a dummy email that you can live with it being full of spam.
Since it is vital to have your email posted on your web page there are two very good methods to prevent spam bots from getting your email. 
One post your email address as an image instead of as text. The spam bots wont be able to read your email address from an image. Or you can use java script to hide your email from bots. It is quite simple, place the following code on your web page where you want your email to be posted. Click here to view the java script code.
If you already have an email box full of spam the above will help stop new spam bots from finding you, but it wont stop the spam bots that already found your email address from emailing you. To filter spam you can use several different methods:
1) Install SpamAssassin – SpamAssassin allows you to configure custom mail filtering rules to effectively filter spam. SpamAssassin is an industry standard and is included at most web hosts. All you need to do is turn it on. If you are using a Cpanel web host you can simply login to Cpanel –> Mail –> Spam Assassin –> Enable.
SpamAssassin Homepage: http://spamassassin.apache.org/
2) Install Spam Blacklists – Spam blacklists (RBL) are independent companies that setup spam traps and blacklist hosts that are sending to them. Spam blacklists are very effective and can reduce your amount of spam by 20-30% if not more. To be effective you need to use the right lists. I recommend using dnsbl.njabl.org : bl.spamcop.net : sbl.spamhaus.org : list.dsbl.org : multihop.dsbl.org
If you follow everything listed above you still may receive some spam, but it will be much less than what you do now.