Coldape:
Yes you can, have done it myself, but also remember you can now play with upto 8 people. So its good to get the wireless ones and have your old wired ones if lots of people playing
Still think this is a good deal, but i'd probably go for ones with the wireless buzzers (not sure what the best price for this is)
Looks to be better with this to buy them as separates:
Buzz! Quiz TV with Buzzers (PS3) Cheapest appears to be £36.99
Buzz! Standalone Wireless Buzzers (PS3) £25.99
Saves a quid and a penny with this.