avi to gif

[adler-wRvlPVLobi1/31tCrMuHxg at public.gmane.org (Stephen Adler)]

Guys,

I've a program which dumps out an animation in .avi format, but I would 
like it in gif so that I can include it in a power point presentation. 
Are there any tools which convert avi files into gif animation files?

(The reason I'm trying to do this is that I have the notion that 
animated gif files are easier to move from one application to another. 
As like I can get them to display quickly in a web browser without much 
fuss...)

Thanks. Steve.