If you're using a newer Nokia phone like Nokia N95 and N82, you can install the JoikuSpot software to turn your Nokia phone into a Wi-Fi hotspot. This means that you will be able to connect notebooks, PDAs and other Wi-Fi devices to your phone and enable them to access the Internet via the phone's 3G/GPRS mobile data function.
When you activate JoikuSpot, your phone will broadcast itself as an adhoc Wi-Fi network, with a unique SSID. You can then connect your notebook or PDA to the Wi-Fi network, just like you would with any other Wi-Fi network. Your notebook/PDA will be able to access the Internet, routed automatically by JoikuSpot to your phone's mobile data connection.
With JoikuSpot, you can easily share your phone's mobile broadband connection with your co-workers, without requiring them to install a mobile broadband modem. It's useful for connecting netbooks (like the ASUS Eee PC) to the Internet, since most netbooks support Wi-Fi but not Bluetooth. From my testing, JoikuSpot worked well with the iPhone 3G for browsing the Internet and downloading applications from the iPhone App Store. The iPhone App Store doesn't let you download applications via the iPhone's 3G connection, so connecting the iPhone to JoikuSpot's Wi-Fi hotspot lets you download applications on the move.
I don't recommended using JoikuSpot for long periods because it drains your phone battery quickly and your phone becomes uncomfortably warm. But I'm happy with the product--it worked continuously for 1 hour without dropping the connection; the Internet connection resumed automatically when I walked away from my notebook and back again (unlike Bluetooth which tends to drop connections); the maximum download speed was 2.5Mbps over 3.5G, when I tested with speedtest.net. JoikuSpot is definitely worth the S$30 (US$20) that I paid for the software.