Although I've written a book about iWeb, I often tell my clients to avoid using it for their websites if they're planning on hosting anywhere but on MobileMe. Why? When you post to MobileMe from iWeb, you "Publish" and your site is uploaded. Minor changes to a site only take a few seconds to upload, since iWeb uploads only the changed files to your web server. That doesn't happen when publishing to other servers. Instead, you publish to a local folder, and then usually upload the entire folder to your web server. That can take a long time with a large site.
Plyxim's Easy iWeb Publisher 3.0.3 fixes that problem. The shareware ($7 donation requested) application makes it simple to publish to any web host. It's an ftp client that takes the local folder you've published your iWeb site to, compares it to the folder on your web server, and then uploads just the files that have changed.
I've found that Easy iWeb Publisher works much faster than most dedicated ftp clients when syncing iWeb files that have been changed, added, or deleted. Until Apple fixes iWeb '08 to make publishing easier for people who don't use MobileMe, this is a great way to work with your own hosting.