Good Antivirus/AntiSpam for exchange server

i m setting up an exchange server for the testing purpose to get more hands-on experience.

Currently, since i am on dynamic ip, i get a dynamic dns from dyndns.org and i setup the smarthost using my isp smtp outbound address for smtp outbounding.

Now, i wanna setup an antivirus/antispam protection for this testing exchange server.

I only have a copy of symantec antivirus corporate edition. but installing on exchange server might be a headache because i have to exclude folders that exchange server uses......plus it doens't protect email messages....so no good.....

i checked cdw and they sell symantec mail security for exchange. however, i dont' need alot of licensings...i might need 2 licenses coz i create two userid for testing purpose....

Can anybody recommend a good one for me? especially free

THank you my friends.