My friend plays 4e and he enjoys the swordmage class. He was wondering if it's in 3.5 so he can use it in a campaign I'm making. Is it?
I'm not an expert on the Swordmage, but it sounds to me like he either wants to play a Duskblade (warrior with some crowd-control and cursing magic) or one of the Tome of Battle classes (Swordsage, Crusader, etc) which are warriors with unique "spells" only they get. The Tome of Battle classes are in the book of the same name, while the Duskblade is in Player's Handbook II (thanks Colin D for that location).
For 3.5e, the simplest close match would be the Duskblade, which isn't in the core books but is in Players' Handbook II. The Pathfinder equivalent to this would be the Magus, from the Advanced Players' Guide.