And to complete the details on history and development; as Warmaster Nice says, the GW "Epic" ruleset has gone through four incarnations. When the third set appeared, a good number of fans preferred to continue with the 2nd edition, so created NetEpic. The NetEpic rules can be downloaded from
this section of the boards
Epic Armageddon is the 4th incarnation (that can still be purchased from GW). There have been some updates to these rules which have now been included in the free downloads available on the
resources section of the official GW site. However, GW support for E:A is restricted; the rule corrections they have published and the development of the army lists is now completely fan based. The GW site also contains the "official" lists, which are considered balanced for games between 2700 - 5000 points.
Some of the other lists in this site are also reasonably balanced, but most are still being developed by the various "Army Champions". The NetE:A committee is trying to bring together the various army lists, watch for developments in
this thread and the various threads for the different races.
Finally, do check out the two 'fan based' supplements referred to by Moscovian. While you can download them, it is worth getting on the list for a printed copy.