==
See Factory Service Manual:
http://oregonstate.edu/~tongt/camry/index.html
---
Usually you'll also change the timing belt, since it needs to be
removed, and oil seals.
Be aware, crankshaft pully bolt on the six cyl. can be very tight.
Place wrench against frame or floor and touch starter, or use powerful
impact gun.

Also check Autozone's free online guide:
http://www.autozone.com/az/cds/en_us/0900823d/80/13/e4/65/0900823d8013e465/repai
rInfoPages.htm

You'll need to get a crank pulley holding tool. http://www.sjdiscounttools.com/sch64300.html
A cam pulley holder helps too.

I'd also replace parts like the following (older prices from www.rockauto.com)
GATES TCK257 timing component kit $89.79
FEL-PRO TCS45890 crank seal $6.27
FEL-PRO TCS45889 cam seal set $8.55
GATES K060410 Alt/AC belt $13.09
GATES K040345 PS belt $8.61
ASCO/AISIN Part # 1610029085 water pump $61.79 (I use Airtex pumps
from the local NAPA store)
Total ~$188 + shipping

If needed: FEL-PRO VS50471R valve cover set (with spark plug tube
seals) $30.79