How can I combine Flv videos just to make one Flv Video?

Ok The Thing is that I want to combine Flv format videos and make it to just one an Example is Lets say I have 4 Flv format videos of FiFa 09 is there any program up there in the internet free or just free trial that can combine FLV Format Videos to make it in just 1 VideoI will reward you with 10 Points For the best Answer !!!!Thanks Guys