Way back when Google first announced Android, its mobile phone OS, the company also promised that eventually the OS would go open source. Google being Google, that promise has now been fulfilled and Android is available to anyone who wishes to play with it, as the Android Open Source Project.
Opening up Android to the general populace is a great way for Google not only to keep competitive with rivals (such as Nokia's recently opened-up Symbian OS), but also to enable developers to take the OS in the direction that best suits them. Currently there's only one Android device on the market, the T-Mobile G1, and as good a device as that is (or isn't depending on who you ask) Google obviously wants to see significantly more devices available.
Letting users tailor their mobile phone or device's is a great way of opening up Android's (potential) install base. It's even possible that someone might come up with a way of getting Android on an HTC device, such as the HTC Touch Pro. HTC being such a huge Microsoft supporter it's hard to see any other scenario in which its handsets would get Google-fied.
Better still for those interested in keeping their illicit applications, perhaps somebody can kill the kill-switch.
In the words of Google: "What will you do with Android?"