Binos
All you need to buy to go wireless is something like an Airport Extreme base station (with modem) and an Ethernet cable.
Airport Extreme base station
The set-up will be something like this:
Firstly, your iMac has got an Airport Extreme card built-in (ie WiFi ready). Using the broadband router that you are obviously using already, use an Ethernet cable to connect this to an Airport Extreme base station. That'll give you your broadband. You can also connect a standard phone dial-up between the base station and the
normal phone socket (use a splitter if you're running a phone from the same socket). Should your broadband go down, you've then got dial-up as an alternative. Also, to the back of the base station, you can connect your printer etc using the USB or Ethernet socket so that you can print wirelessly (this makes the printer a wireless
network printer). That way, all the hardware can be kept in another room out of sight. However, as far as I know, it's not yet possible to scan wirelessly.
Having set up a wireless network, your PC can simply join it as it would do any other WiFi network (provided it is WiFi capable) and can use all the same connections (broadband/printer/dial-up etc).
If you want to go one further, you can also get one of these:
Airport Extreme with Air Tunes
.... but that's just getting flash!
Bluetooth is great for things like a wireless mouse or keyboard and for connecting to a bluetooth enabled mobile phone. You can then download music, piccies etc to your phone. Depending on your phone, some will interface with iCal etc as well. You can also use the bluetooth phone as a wireless modem (using GPRS) when away from home in the boonies to give you internet access etc.
Hope this helps and gives you an idea of how simple it all really is.
Trips