Follow the air induction rubber boot from the air filter housing to the throttle housing on the intake manifold. The throttle position sensor is located at the firewall (rear of the engine compartment) just next to that black rubber boot.
I have a 98 prelude SH so i know were it is. its behind the throttle body. Bad news is it cant be remove with a screw driver or any other tool. The TPS is held by two screws/bolts with no head, so you have to cut across the bolt so that you can use a flat head screw driver or u can try needle nose vice-grips to remove them. It can be replaced but you'll need to use a voltmeter to adjust it to Honda specs. Another problem is that Honda dose not sell the TPS separately. They sell it together with the throttle body as one part, but you can buy the TPS from Blox here is a link http://www.bloxracing.com/bloxshop/index.php?route=product/product&keyword=tps&category_id=0&product_id=169
if u need any more help let me know.