The Adrenaline Vault posted a list of the top selling games for April.  They are:

1. The Sims: Vacation from EA
2. Dungeon Siege from Microsoft
3. The Sims from Electronic Arts
4. Jedi Knight II from LucasArts
5. The Sims: Hot Date from EA
6. Medal of Honor: Allied Assault from EA
7. Starcraft: Battlechest from Vivendi Universal
8. Roller Coaster Tycoon from Infogrames
9. Spiderman the Movie from Activision
10. Zoo Tycoon from Microsoft