assign file extensions to programs

Hi,

sorry if this was answered before. How can I tell my iMac to open e.g. avi always with a certain program? I only get open this specific file with a certain program, but not ALL avi's.

Another thing, maybe someone knows: iPhoto always wants to add some files, but the question always comes, no matter what I click on.

Any help much appreciated!

Select the file by single clicking.
Use Command+i to open info
There is an Open With section with a Change All button that should do it.

Perfect! Thanks a lot!