Both are used for connecting to EZ VPN server
Hw client is box ( available with or without an 8-port switch)Hardware Client is designed for organizations with many remote office environments because it easily scales to tens of thousands of devices
SW client is software installed on PC - is designed for home office or for travelling users
M.
Chcek following links
http://www.cisco.com/en/US/products/sw/secursw/ps2308/index.html
http://www.cisco.com/en/US/products/hw/vpndevc/ps2286/index.html