Other good GBA tactics-RPG games: Onimusha Tactics Tactics Ogre: The Knight of Lodis Shining Force - Resurrection of the Dark Dragon Zone of the Enders: The Fist of Mars
Oh, you mean emulating phone games on the PC? The only emulator like that that I know of is Microsoft's Device Emulator that supposedly emulates Pocket PC 2003, Smartphone 2003, and Windows CE 5.0, but I've never really gotten it to do much. :/
Yes, the GBA flashcart will work just fine in the DS's GBA slot for playing GBA ROMs. As for a slot-1 device, I'd suggest either an R4 DS or a CycloDS Evolution. Both take microSD cards. If you want a device with built-in storage as well as a microSD slot, the Acekard R.P.G. seems to be fairly decent.