For me, SW GMing always starts with cool locations, so I'll start there.
A good starting point for maps is the Star Wars minis gamer community, which (inevitably) produced a lot. Some are a bit cramped or busy, as they were designed for tactical interest in a skirmish wargame, but in a lot of cases that only makes them work better for RP.
Some links:
For tiles, I'm quite fond of TileSystem, an editor originally written to handle maps for FFGs Doom. The tileset style isn't perfect for SW, but the Doom and Space Hulk tilesets are good for rapidly sketching starship/space station maps. (I prefer pyMapper, but nobody's adapted any good SF tilesets for that yet that I know of.)
There's an archive of NPCs, droids and creatures for Saga here:
Also, my favorite tool for starting SW games with a bang: the word processor. For SW I always borrowed the old West End Games trick of starting the adventure in media res, with a short script for the players to set the scene. It suits the genre, and gets things moving immediately. (I prefer to take a tip from Lucas, back when he had a decent editor... Star Destroyer full of troops boarding a corvette first, slow down and establish plot second.)