Maybe I'm the last to find out about these things, but The Google Chrome Web Store looks like the first really promising way to monetize web apps written in Flash, HTML 5, Silverlight, etc. It appears to work on the sample principle as the iPhone store, but make apps available to any browser that is HTML 5 compliant.
Creating apps appears to be very simple. Here is what Google says in their docs:
"You can easily make any existing web app installable.
There's no need to rewrite it or change technologies. Alternatively, you can also create fully offline, or "serverless" apps."
ANY app? Wow. They continue with this information about the store itself:
"The Chrome Web Store is an open marketplace for web apps
that will enable you to reach millions of users with your apps.
The store will be integrated with Google Chrome,
making it easy for Google Chrome users
to discover apps and install them directly from the store.
You'll also be able to sell your apps using an integrated payment system.
If this holds true, you can create a Flash, Silverlight or HTML 5 Canvas game or app, host it in a web page, and sell it in the store. You can create the app as stand-alone, and save data to a Flash Shared object, or to the HTML 5 browser storage. Alternatively, you can make the app server-side compatible, multi-player, etc. (apparently).
To me, this appears to be the most promising technique yet to monetize games and apps on the web. I like that Google has taken (what appears to be) to opposite tactic from Apple. They will allow ANY app into their store, as long as it runs in web browser. That appeals to me very much.
To get involved developing for the store, it looks like you should start here: http://groups.google.com/a/chromium.org/group/chromium-apps/topics