If you are looking for an email provider for your website, Google provide a very affordable excellent service as part of their Google Apps offering which includes spam management.
If you would like to us google apps with your hosting, all you need to do is sign up with them, create the user accounts and point your domains MX records over.
Pricing at April 2013 is $5/user/month.
Please note this is a Google product which we recommend but cannot offer support on in any way. Any questions or support issues you have should be addressed to Google support who provide well documented guides on using their system and configuring your mail program.