Logos are a very important part of your web presence.  You could try to create one yourself using a graphic program and that might be fine for a personal website.  For a commercial website, you will probably want to have a logo created professionally.  A logo is a very important part of your business and not something to scrimp on.

You could go with a local graphic design business or try an online freelancer website.

Another option is to use a site like AAA Logo.  This website works like a template and assist in creating a logo.  Not a bad idea starting out but nothing will beat have a true professional create your logo.