Folks are still getting things organized, so this list will expand and get more detailed . . .
United Kingdom
Massive action in London to celebrate diverse struggles against capitalism, exploitation, and destruction of the planet, preceded by a four-day gathering starting April 28th, including workshops, speakers, discussions, a bookfair, a film festival, Critical Mass, plans for a permanent social center, etc
Manchester and Sheffield are also organizing events.
New York City
May Day parade, including actions and celebration.
San Francisco
Action in downtown against capitalist targets; celebration and a picnic. sfmayday2000@yahoo.com
Washington, DC
After the city gets shut down on April 16 when the IMF and the World Bank are in town, DC will be ready for a cool May Day celebration including: music, food, speakers, workshops, tables from liberatory organizations, etc.
Chicago
Marches and unified protest downtown, with actions, shut-downs and anti-capitalist carnival. Possible targets include major corporations, the Board of Trade, maybe the whole city.
New Orleans
Rally and march in Congo Park including an autonomous anarchist section.
Eugene, Oregon
May Day action and celebration.
Gainsville, Florida
Camp-out in the Everglades, labor video festival, parade/dance/cavort event, a speak-out and celebration to be held on pirate radio, and a workday to make puppets and other crafty displays.
Olympia, Washington
May Day celebration.
Phoenix, Arizona
Carnival against capitalism.