Preparing for a high traffic site

[FiRe]

I am about to begin developing a web 2.0 site which I expect seriously high traffic from. It will be done in PHP/MySQL and Ajax. What sort of things should I be doing when I code this site? For example, should I use mysql_pconnect over mysql_connect? Should I use classes instead of functions? Also what would you recommend I tweak in php.ini? Does anyone have any other suggestions? Thanks for your time!

[peterdaly]

Cache dynamic content where ever possible so it does not need to be regenerated for every page load...especially if it is pulling from a database...although depending on how you do things, the cache itself could be in a database.