Email address, web site, or domain?

What's the difference between an e-mail address and a web site address?  They're just two different resources.  If there's an @ sign it's e-mail.  That's your mail box.
If there's an http:// it's like a store front, that is, your web site, where your product information sits, e.g., images, contact information, description of what you provide, and possibly interactive elements such as response forms, hyperlinks to other sites, and much, much more.  There are other resources under a domain, like FTP, but this gets into issues on the hosting environment.  Basically, different resources are distinguished by their transfer protocol (e.g., FTP vs. HTTP), but they all "live" under the same domain.
If my domain gives me a me@mycompany.com does that mean I automatically get e-mail?  Service yes, if you host with Open Veld and most other hosting companies, but you still need to pay for internet connectivity.  That is, you need to pay or continue paying an Internet Service Provider or AOL or someone to allow you to log into their remote modems.  The ISP or dedicated line is your on-ramp to the internet.  With all our full UNIX hosting plans, you can either use your me@mycompany.com as your POP3 and SMTP mail server, or you can just have your domain forward e-mail to the same old ISP address.  By comparison, the $48 UniWeb Parking plan covers e-mail forwarding only.  For two years.  If you also just want a single web page, we can set that up also for a minimal charge.
What's an http://www?  The http:// tells your Netscape or Internet Explorer browser to look for a typical web page type resource; the www is just the machine name.  Occasionally you will see www2 or other machine names or just leave it off.  The better hosting arrangements such as Open Veld allow for people to reach your web site by typing either http://www.mycompany.com or http://mycompany.com  Less typing, less chance of mistakes.