Since android doesn't support opening the market from web views. This seems like a pretty good hack. Idea from http://stackoverflow.com/questions/3583264/support-for-other-protocols-in-android-webview

gistfile1.js

  webView.addEventListener("load", function(e){
	if (e.url != null && e.url.indexOf("market://") != -1) {
	        // Open the URL from the device
		Titanium.Platform.openURL(e.url);
		// Reset the URL to the initial one
		webView.url = url; // url is set somewhere in your code
	}
});