For anyone who is going to run an epic game there are a few recommendations I'll make, as my experience with prior games has generally shown.
Make the premise of the game clear (plane hopping, epic quest against evil, etc.)
List all the sources you'll allow without question (the smaller, the easier to deal with)
List sources you'll allow on a by-approval basis
List stuff you won't allow explicitly
Say if you are using errata or not.
List races you think appropriate for the game. (i.e. all humanoids is easier to deal with than a mind flayer, a dragon, a gelatinous cube and a human).
Make attribute generation explicit (higher point buy works well at epic levels)
Give an XP amount rather than a level.
Give a GP amount for wealth. State how much they can spend on items.
Be careful allowing custom items, they open a giant can of worms. (let me reiterate this again, GIANT!)
Ditch epic spellcasting & psionics (too much hassle and generally breakable)
Make interpretations explicit on questionable stuff early
Be especially careful of anything that would remove expensive costs of XP, Gold, metamagic spell increases, (dweomerkeeper supernatural spell, divine metamagic, as examples)
Be wary of persistent spell.
Spellcasters can easily dominate in epic games, be sure to make all characters feel on equal footing.
Be the final arbiter, don't let players debate stuff, it gets out of hand.