I asked the same thing a while ago and the answer is to go to the WA TAB website.

http://tabform.thewest.com.au/

Sign up (free) and they'll let you see their pre-post prices. These are computer generated and so far I find them accurate enough. Certainly more consistent than my morning newspapers. I use these pre-posts on most of the systems I run and I believe my results have improved since doing so.

A good site. Except they remove the forecasts after the race has run, which is annoying.

The issue of prerpost prices on-line was discussed quite a bit on threads in this forum a few weeks back.

Hermes