I want to set up an e-mail server so that me workers can have their own e-mail?

Well, I looked everywhere. I need to simplest solution that will also not be the most expensive. I want all of my workers to have their own e-mail accounts so that they can get e-mails on their PDA's. For ex. bob@bobsmaintenance.com. Something like that. I already tried to go through GoDaddy.com and that only created havoc. I want to do this in the most simplest way. Im not the best with computers, but I do know a lot. Just not this unfortunately. Thanks if you can help.