Under Mac OS X 10.5 (Leopard) there is a way to put these web applications back on the Dock, where they belong. Fluid is a beta application that take as input a web URL and then packages up a Site Specific browser that runs in its own window, independent of Safari. The app appears in the Dock like all other apps and runs in its own space. My first test was to run Gmail in its own window to separate it from everything else I am doing in my browser. So far, it is working splendidly. It even shows me the number of unread emails in the Dock icon, just like a standalone email application.
You can try out Fluid for free using the link below.
Link: Fluid - Site Specific Browsers for Web Applications - Mac OS X 10.5
From their web site...
Are you a Gmail, Facebook, Campfire or (Insert Your Favorite Webapp Here) fanatic? Do you have 20 or more browser tabs open at all times? Are you tired of some random site or Flash ad crashing your browser and causing you to lose your (say) Google Spreadsheets data in another tab?
If so, Site Specific Browsers (SSBs) provide a great solution for your webapp woes. Using Fluid, you can create SSBs to run each of your favorite webapps as a separate desktop application. Fluid gives any webapp a home on your Mac OS X desktop complete with Dock icon, standard menu bar, and logical separation from your other web browsing activity.