~ Can i know if there is a any product meeting the above requirement.
~ If so, can i know the product, its better if it comes with a chipset
~ that supports promiscuous mode.
First I assume that by "PCMCIA" you really mean Cardbus. (PCMCIA was
an older PC card standard which does not provide enough bandwidth for
"54Mbps" 11a/11g applications.)
There are many Cardbus cards that support 802.11a/b/g including the
Cisco Aironet CB21AG and the Linksys WPC55AG.
Next question is about promiscuous mode. Assuming you're using
Windows, the main issue there is that Windows drivers normally
prevent promiscuous operation. There exist for-$$ wireless
packet capture software packets (such as the relatively inexpensive
Commview for Wifi) that will allow a Windows PC promiscuously to
capture wireless packets. I am not aware of any such free
software worth mentioning.