Eastway Cycle Circuit, Temple Mills Lane, London E15. Access is actually from Quarter Mile Lane, which can be found on the southern side of Ruckholt Road, the A106. Fairly close to the New Spitalfield Market, if that's any help. More detailed directions are a bit pointless due to the perpetual construction of the M11 Link Road; the situation on the ground doesn't look much like any map, and changes quite frequently. The map below should give you a rough idea of where things are:
Nearest tube station is Leyton, on the Central Line.
Typically, racing consists of a couple of 1/2 hour scratch races for the championship chase, plus a "fun" race in the afternoon.
Check out the Photo Gallery for pictures of the 2003 and 2004 AGM events.