With Apple removing Mobileme this year, I am sure some people have their blogs hosted on the Mobileme servers. You could possibly move your iWeb site to another hosting provider, but then as there has been no change to iWeb in a while, I am not convinced this application will be around in the future. I thought if they were going to keep the application then there would of been some development to it.
There is a way that you can convert your blog over to Wordpress (then from there you could migrate it to a different platform i.e. Squarespace :-)). There is a piece of software from Rage Software that will allow you to do this. I have not tried this software myself yet, but soon I maybe using this as there is a site I have created for a client and they may want it migrated off of iWeb so it can be updated easier and more frequently, this way they are not limited to working at home on their Mac. You can download the software from the following link.
http://www.ragesw.com/products/iweb-to-wordpress.html
I am always interested in your thoughts so if you have any comments or feedback then please feel free to add any comments, or you can mail me here.