I've got a fairly active blog, and host a very, very active podcast. All told, I run about 30 sites, all on wordpress.
If this is for a commercial endeavor, you ABSOLUTELY need to host it on your own domain. If you commit to a hosted blog on wordpress.com, you give away all of the accrued value of your blog address.
If you go with one of their
recommended hosts, you can install wordpress with just a click of a button. If you go with dreamhost, I can walk you through the process. Shoot me a PM.