I you are looking to host your iWeb web site. You can continue to, use iWeb but, will need a 3rd party web host to upload your websites to. Depending on the version of iWeb you are using you have a couple of publishing options:
iWeb '09 (3.0.4) you can publish to an FTP Server or a local folder. ( With the built in FTP in iWeb you will end up with an address like "www.YourDomain.com/sitename/Home.html )
iWeb '08 you can publish your website to a local folder, then upload to a web host with an FTP application like CyberDuck
I have been using IX Web hosting for several years with little to no problems "usually the problem was something I did" and they have been quick to solve any issue I have come across. The have plans that start at $3.95 a mo (USD) and their customer service is top notch.
"I may receive some form of compensation from my recommendation or link."