This is a question that has come up before but, to the best of my knowledge, there is no simple and direct way to do what you want to do. However, I think I have figured out a way to do what you want to do but you will have to do a little math. This method is based on the fact that each forum page contains 20 posts.
Using your example of wanting to go from page 38 to page 90 of Omid's thread, you will note on page 38 (http://www.pizzamaking.com/forum/index.php/topic,14506.740.html
) that there are two numbers at the end of the URL in the address bar (before html). Those numbers are 14506 and 740. The first number is the topic number. The second number is page related. Now, if you want to go from page 38 to page 90, you perform this calculation:
[(90-38) x 20] + 740 = 1780
Once you replace the number 740 in the URL with 1780 and hit Enter, you should end up on page 90.
The above may seem like a lot of work but in many cases it will be a lot faster than clicking two pages at a time, especially where the thread is a long one and the page spread is wide.
To go in reverse, you would do the math in reverse, e.g., going from page 90 to page 38.