For tilemaps I tend to roll my own but there's stuff like Mappy out there -- scroll down and there are even some Blitz libraries for it.
GTKRadiant (now GPL & open source) is the variant you want for Q3 map construction... just compile to .bsp and B3D will load 'em.
GTKRadiant (now GPL & open source) is the variant you want for Q3 map construction... just compile to .bsp and B3D will load 'em.