Playmates Toys gave us some tentative info on the 2004 lineup:

Series 15:
-Handsome Moe
-Brandine
-Octoplets (all 8 on one card w/ stroller)
-Deep Space Homer
-Comic Book Guy (rerelease)
Celeb Figure: Manjula (*voiced by Jan Hooks*)

Mail-Away: Stonecutter Krusty

Series 16
-Agnes Skinner
-Benjamin and Gary
-Doug
-TBA
-TBA
-Celeb Figure: Young Artie Ziff (*voiced by Jon Lovitz*)

*Mail Away: Stonecutter Lenny

Other planned 2004 figures:
-Tuxedo Kang
-Tuxedo Kodos
-Lindsay Naegle
-Sanjay
-Bigfoot Homer
-Arnie Pie
-Hellfish Grampa
*Nipple Suit Apu
-Akira (*voiced by George Takei*)
*Celeb Figure: Cecil Terwilliger (*voiced by David Hyde Pierce*)
Mail Away: Stonecutter Carl

Playsets:
-Series 15: Nuclear Power Plant Breakroom (w/ Frank Grimes)
-Series 16: Town Square (w/ Jebediah Springfield)
-Series 17: Springfield Elementary Playground (w/ Janie)
-Series 18: Flanders Rumpus Room (w/ Maude Flanders)

*TENTATIVE (Final list pending approval)

Miscellaneous notes:
-Each new series will include 5 new figures and one resculpted rerelease
-The Burns/Smithers Diorama 2-pack will no longer be a Target exclusive.
It will be mixed in with the first series after it ships.
-An upcoming Diorama set will be Bart and Lisa
-Another upcoming Diorama set is Chief Wiggum and Eddie
-There will be a Season 15-based exclusive set
-Poochie may be added to this lineup, possibly Series 17
-There will only be 4 Stonecutter mailaways
-If the Stonecutters are popular, we may get an exclusive Stonecutters Hall playset
-The original kids scale will continue (Database was an error)
-Figures originally included in playsets will be rereleased individually carded
-Likely no more celeb-as-themselves figures and NO President figures
-Drederick Tatum and Lucius Sweet are no goes due to legal concerns
-Tux Kang & Kodos will be separately carded
-The Town Square will feature a Jebediah statue w/ removeable head AND a Jebediah figure
-Figures considered but not planned: Sam and Larry, Rich Texan, Very Tall Man

Thanks to Playmates Toys for for the info.

Toy Show Images