97 Astro Fuel Pump

How hard is it to replace the fuel pump? I know I have to drop the tank. Do I need any special tools? Any place online to see a good diagram of the process?

Autozone.com has repair guides. They only have guides up through the '95 or '96 year model, but it should be very close to what you have.
Here's a link: http://www.autozone.com/servlet/UiBroker?ForwardPage=/az/cds/en_us/0900823d/80/12/c4/e3/0900823d8012c4e3.jsp
On the '96 and later year models the fuel pump is held in place with a large snap ring. If you don't have snap ring pliers, you'll need some.
Don't forget to relieve the fuel pressure on the fuel system first.

I replaced the pump on my '97.
The hardest part I found was the "quick connects" at the tank, about a half hour each due to corrosion. (3 of them)
I needed to raise 1 side of the van, by using 2x6 wood, to get it high enough to get the tank from under the van. (no running boards) I blocked the front and rear of the tank on many wooden blocks to 'see-saw" the tank to the ground. Fuel is about 7 lbs/ gallon, and it sloshes around.
The fuel fill line has another rubber pipe inside the 1 you see, and is also cause for a few words.
I don't remember how I got the pump out, I didn't have a problem with the snap ring, I probably tapped it out with a brass drift.
A few people have said they broke the welded nuts out of the frame. I soaked mine the day before I worked on it. And you can save some time if you remember which strap is front and which is back.....
Pay attention to the way it comes out, re: fuel level sender. At least it doesn't matter if you bought the assembly.
Also, MAKE SURE the electrical connector is in mint shape, no signs of melting. My assmebly came with an electrical grease for that connection. There's about 10 amps flowing thru there while the engine runs, and the connector may overheat.
Not too bad a job. I think it took me a half day. (but spray the tank bolts a day before)

i just did a pump on my 95..the 97 is pretty much the same except has a snap ring to hold in the pump/guage assembly. just pickup some snap-ring pliers if you dont already have them. the hardest part is getting the fuel out of the tank. there is a anti-theft bend in the filler tube that makes it really hard to syphon out...disconnest the filler tube and syphon out through the opening of the fuel tank (where the tube goes in)you have to remove this anyways to drop the tank. like drew said (above) soak the fittings and the tank strap bolts. i had a hard time with my fuel line fittings...but after a good soak for a few hours i got them free. the empty tank is actually quite light and with two jack stands on the rearend you have plenty of room to lower the tank out and pull it out through the drivers side. i used the haynes manual i bought from autozone and followed the directions...not a hard job. but just be cautious not to spill any fuel and remember the fumes are flammable too so keep your garage well ventillated. i did have a problem with my electrical connector and could not get it off...so i cut my wires way up by the tranny and then soldered and taped them up after i installed the tank again. work very clean because you dont want to get any dirt or anything in your tank or on your new pump...also replace your stainer with the pump. hope this helps...i just did this last week. good luck!