could anyone here tell me what are the differences between these two wireless technologies? let say i have a Wifi cell phone, can i connect it to 802.11b/g wireless network, and how?
Do you actually mean a "wifi cell phone", or do you mean an internet-enabled cell phone?
Grumpy answered, I think, assuming you mean internet-enabled. The high-speed service provided by cell providers is distinctly different from 802.11 wifi. This includes the broadband services offered by such cell providers as Verizon.
However, there have been some wifi-enabled cell phones offered. Motorola offered one that could connect with 802.11a, and HP has a combo cell/wifi device in ther iPAQ line that could connect with 802.11b or g (or maybe both - I forget). There may be others. Features supported vary with the device.
What model cell phone do you have or are you considering? Check with the vendor. They can tell you what it can do with wifi.