Hi, I am new to this, But I have lent a bit, Here goes :-
1. Use Quake III BSP's ( The programs I use are G-Max, Tempest, and gtkradiant ). Web addresses are G-max
http://www.discreet.com/products/gmax/ and gtkradiant
http://www.gtkradiant.com/?data=files&files_id=26 Also you must have a copy of Quake III and a copy of PakScape.
2. You must pack your bsp's within a PK3 file as well as your textures and some shader script files. ( Make your Bsp's with G-max-Tempest then save it as a map file then use gtkradiant to make your BSP ), Then use Pakscape to pack it to a pk3 file and remeber to take the textures and script files from Quake III Pak0.pk3, and put it in your own pk3, So you should have three Dir's in your PK3 file (Maps,Textures,Scripts)
3. From with in DBP use the command ( load bsp "Test.pk3","Test.bsp" ) to load you Bsp map.
You should only use the Quake III files as a leaning tool, Don't use Quake III's textures or scripts in your on game that you are going to sell or give away ???
Hope this helps, and if I have got anything wrong sorry, But maybe someone else will correct me.
Ps. I Use Quake III because they show Animated textures like lights and swirly effects on the Bsp.
TechHead