There's both sides of pair programming... recently I attended a presentation where the presenter basically said that pair programming should be mandatory... on the other hand, I've done pair (and even triplet) programming... Here's my thoughts:

* Advantages - Works great in initiating a new team member in to a large project - Gives each developer a chance to do code-review on the fly - If there's good rapport, pair programming can get a lot more done

* Issues - Requires good co-ordination between team members - Two similar thinking people may not be able to take full advantage of this technique