GLOBETROTTERDK  Try rooSwitch here at MacUpdate. Not only does it work for iWeb, but it can setup profiles for the other iLife apps as well. Also works with iLife '08.  
(Version 2.1)

GRYPHONENT  Maybe worth $5. Definitely not $20. Also, iWebsites does the same for free.  
(Version 2.0)

KATHYMAC  After struggling to figure out a way to publish and host two different sites on iWeb to two different places, I did a web search and found Multisite. I downloaded the demo and within a couple minutes had it installed and was able to use it to manage multiple sites in iWeb, publishing one to a folder to upload to my work server, and published the other to my .mac account. I immediately purchased it. Much easier than having to locate, rename, and move files manually. It's main feature is allowing management of multiple sites in iWeb without having iWeb publish ALL sites to the same place every time. Ridiculously easy to use. Great price for a product that eliminates a lot of frustration. Have had no problems at all with it, functions perfectly with OS X and iWeb.  
(Version 1.6)

MACLOVER1.1  I tried iwebsites which is free and felt really dumb because it kept "bouncing me back" to the same.. website, or at least what seemd to be.. I must have done smthg wrong... then I tried this.. and it is straightforward.. very much so.. just what I was looking for in the first place... so I guess I'll pay for this lol  
(Version 1.1)

GTE037P  The demo works as it should.. but iwebsites works as well for free.. this is pretty though.   
(Version 1.0)