No, bluetooth and 3G is different technology. Bluetooth is a
data transmitting technology most used for wireless headset and
data transfer to PC. It is not a phone network, so u don't compare
it with 3G, rather u can compare it with infra-red or USB data
transfer.
3G stands for 3rd-Generation phone network.
The 1st-generation phone (1G) is the bulky handphones u see over 10
years ago without SIM cards and everything are hard-wired.
The 2nd-generation phone (2G) is what most of us are currently
holding, a phone which is independent from the operator with the
use of SIM, regardless of which network u are on, eg. GSM, PCN,
900, 1800, 1900, etc. The bandwidth of 2G phone is limited to 9.9
kbps which u can hardly use it to surf the net, perhaps good enough
for email only.
GPRS is sometime called 2.5G b'cos its bandwidth can reach 128
kbps, which is useful for normal internet surfing, search, download
of games, wallpapers, screensavers into your phone.
But 3G phone is much more superior ... its bandwidth is 1 mbps
(i.e. 1,000 kbps) !!! It is so fast that users can now communicate
more than just Voice, but also Video. Hence, VIDEO CONFERENCING or
face-to-face realtime communication become a reality.
So basically all your previous handphone or SIM cards won't be able
to support 3G, and u would need to buy a new video-conferencing
handphone and to subscribe for a totally new plan from the
operators when it fully launched commercially in late 2005.
I look forward to the day when I can SEE the person whom I talked
to over the phone. I LOVE 3G !!! 
