Newbie S/S question

Hi all

I am new to server side stuff because my clients are small business, but clients want to manage their own sites more these days. So I need to know more about the difference between php and asp, and what are some of the best content management solutions for small busness given their small budgets?

Or should they purchase a product like macromedia’s contribute (though i doin’t know the cost of that as yet).

thanks for assistance with this …