How do I know what applications are updated in the Android Market?

Some of the applications I have loaded appear with the word "Installed" to the right of the application name, but others still have the word "FREE" shown. Are these applications updates? Did the developer just resend them to the Android Market to appear higher on the By Date listing? Why don't all of my applications that I have loaded show up as Installed? Why isn't there an Updated tab to help me know and manage applications or at least something like an "Update available" label? How are you supposed to know what version you have loaded so you can compare it to what is shown in the list?

I am still very disappointed that I cannot try out more applications because I am limited by the available memory on my G1. I was encouraged to see SplashID in the most recent list of available applications because this has been available for Palm, Windows Mobile, and S60 for quite some time and I am glad to see mainstream developers joining the Android community. Other applications I have seen on other platforms include IM+ and Funambol.

There is also a second video player (PlaysVideo) in the Android Market, a few tip calculators, task and notes applications, RSS reader, a second Twitter application that I find to be better (Twitli), and more. I still want to see a podcatcher, better camera application, and Exchange client. There are still only 30 games available and I only find a few to be worthy of installation. I expected more games since that seems to be the most popular downloaded category of application on every other mobile OS. Maybe the game developers are waiting for monetization of the Android Market.