User accounts in Mail versus Alias

Is their a way to create a "signature" for an "alias" mail account in mail with mobile me or is it possible to set up an additional mail account for a single user plan of mobile me? I used iweb to create a site that I want to use for a specific purpose and I don't want to use my regular email when viewers on my site email me.

Any suggestions or resources to get more info. on mail user accounts would be greatly appreciated. I have found help topics about about creating additional email accounts (with gmail etc....) but I'd prefer to have both of my accounts with mobile me.

Thanks!