Making Gifs From png

HOW DO I MAKE AN ANIMATED GIF FROM SEVERAL PNG FILES?

I use Animation Shop 3 that came with PSP. Do a search on animated gif creator and you will find lots of applications to do the job. Should be some free ones available if that is what you want.

thanckx mate.. ill have a look..also does it feature invisible background? just so it wont be a block colour in the background?

thanx

OK I FOUND OUT HOW TO MAKE INVISIBLE..BUT KNOW WHEN I MAKE IT INTO AN ANIMAITON IT SEEMS TO ADD EVERY FRAME BEFORE THE NEXT FRAME SO THE LAST FRAME OF THE ANIMATION ALSO CONTAINS ON THE SAME FRAME ALL THE OTHER'S BEFORE IT..I DOT WANT THAT..HOW DO I FIX THIS?