Any recommendations on a good anti virus program for my Mac. My internet provider suggested I run a virus check. I have been getting emails from myself and I'm told someone has hacked in and has my email password.
What version of OS X are you running? If you are running OS X 10.6 (Snow Leopard) or later, then AV software is largely pointless. There is very little malware for OS X, and Apple has built-in protection (known as XProtect) that they update automatically in the background as needed. I am of the opinion that it's a good idea to have 3rd party AV software available to run once in a while as a "second opinion", and
ClamXav is good enough for that. Just don't use the Sentry option... that keeps it running all the time and just isn't necessary.
That all said, if someone has hacked your email password, they wouldn't need to have done so by hacking your Mac first. If you have "weak" passwords, or re-use the same password, then they could have guessed it or re-used it after discovering log-on credentials you use on any of the hundreds of websites that have been hacked over the past years. I assume you have changed your email password by now? Also, they may not actually have your email password, but forging emails claiming to be you. A lot of Windows malware does that exactly.... they mine the address book on a compromised Windows PC and fake emails from the people in those lists. In other words, you may have an acquaintance whose Windows PC is infected and it is pretending to be you because your acquaintance has your name/address in his contacts.