<a href="http://hem.passagen.se/flubba/gba.html" target="_blank" >FluBBa</a> has released a new Sega Master System emulator for the GBA (works on Nintendo DS and Gamecube Gameboy Player too), this release is considered beta and contains a new Rom Builder by Loopy:

Heres the older release news:

V0.2 - 2005-08-02 (FluBBa)
Fixed sprites in Golvelius.
Fixed hanging in StarGate.

V0.1 - 2005-07-30 (FluBBa)
Initial release.

V0.0 - 2005-07-06 (FluBBa)
Started Coding.

Download Here --> http://gbaemu.dcemu.co.uk/smsadvance.shtml