If your already getting a lot of spam on your main business email address, you'll need to start filtering it somehow. If you have access to the server you get your mail from and it's a Linux box, you can run something like SpamAssassin.
You can also setup mail rules in your email application, but that's a real mission.
A few tips to prevent getting tons of spam :-
1. Get a gmail/yahoo type account to use on the web for all forms/forums - almost everything. Never let your business address near any web form. Gmail is perfect for this, as it has it's own build in spam checking routines. Obviously your not going to want to use that gmail address when ordering something online
2. Get a email inbox checker, something like eremove :-
http://www.snip.net/help/eremove.htm
These types of programs will login to your mailbox and return just the headers from the email, you can then delete any mails that you want. The good thing about this is that sometimes spam contains hidden images etc. that add a log to the originating server when accessed, which allows spam sending programs to know they've got a valid email address (this is just one method)
Another cool thing about it is you can check for large attachments, you know, the stupid 1meg pic you've seen 50 times before - that type of stuff.
3. Change your email address over time - this is something I did over a period of 3 months, notifying everyone to update thier address books. I eventually received just spam on the old account and terminated it. I had to do this because my old address had been out on the web since 1998, before spam was a real problem, so the damn thing was everywhere - I must've been on every spam database on the planet. Even using SpamAssassin would still see me getting 20 spams a day.
My new account I get about 3 a day, which I get rid of with eremove. It's been like that for a year now, so I'm winning the battle using my simple methods.