in reply to Extreme programming... in perl?
In my experience, the biggest problem is to persuade the organization you are working in to allow or even encourage pair programming. Most big organizations seem to feel pair programming is a waste of time (of course it is not!).
In contrast, I feel that pair programming is responsible for the biggest change effects that Extreme Programming has to offer - better team work, more people "in the know", faster learning curve for everybody on the team, cleaner designs and code, less "quick and dirty" work, more fun.
The other big thing about Extreme Programming is the emphasis on testing, obviously. But this has been there before - just read chapter 6 of The Practice of Programming by Brian W. Kernighan, or chapter 25 of Code Complete by Steve McConnell.
Brainbench MVP for Perl