how to detect my web cam in ubuntu 10.04 LTS

i install ubuntu 10.04 LTS.. but dont know how to installl some softwars ..
mostly i hve webcam autodetecd and autoinstalld without any drivers. i used this in yahoo messenger in windows xp..but in this ubuntu i cant.. no video calls ,,cant watch videos ,i seen many softwares to install wat i want ...but wen im going to download ..it occours errors to download..one of them ..one error is "GStreamer encountered a general supporting library error."...dont know wat to do...
im good in windows xp but i also want to know more abt this ..plz help me..
regards
Mandeep Singh