Lots of questions... Yes, it's an obex push of our own Symbian C++ app. Our app is C++--not Java. That's why it runs on Series 60. However the part that runs on the phones is super simple. The hard part is the software which runs on the PC--it handles all the logic and renders the screens. The phone software only displays graphics and forwards keystrokes, so it would be easy to port to J2ME.
Regarding navigating, the phone's joystick moves the mouse, and you can type. However, normally if you really want to use the webpage you use a tablet orbiter or a wireless k/b and mouse. The phone is just normally used for static pages, like weather or traffic, where you hit a button to view and another to close.
Yes, the connection is always there. The connection doesn't drain battery life, but leaving bluetooth on does.
re: lack a general part... Could you be more specific? What were you looking for? Where did you look, and where did you expect to find it? If you have specific recommendations I can forward them to the web site team--they're always tweaking the site to try to make it easier to use.
For controlling other things, you use whatever PC controllable lighting/automation devices you want, like x10, Lutron, 1Wire, EIB, etc. You could build your own and write drivers, although some devices are so cheap it's not worth it.
Yes, everything works in Europe--we have lots of installations there and dealers too.