The maps are Japanese Castles, Schadenfreude TA, Crossed Paths, and An Iteration of TA Hell. Here is a quote from Paulis .plan.
id has just released a map pack containing four team-style maps approved for use with id Softwareis Quake III: Team Arena™ computer game. Their creators are some of the most talented mapmakers in the Quake community. Working together with id designer Paul Jaquays, Quake3World Level Editing forum moderator Astro Creep, Mr. Elusive, the bot A.I. programmer for both Quake III Arena and Quake III: Team Arena, and Drunken Boxer, Quake3World Capture the Flag and Team Arena forum moderator, these artisans have created some truly fine playgrounds for Team Arena.
You can find the Quake3 Team Arena Map Pack at the Blue News Web site. The Map Pack is a cross platform download.