boeffl points out that the official PC requirements for Indiana Jones and the Emperor's Tomb are now up on LucasArts.com.
According to these specs, you'll need at least a Pentium III 733mhz, 128 megs of RAM, and a GeForce 1 video card to play this game. Oh, and at least a 4x CD-ROM... but really, if you have anything less than a 16x CD drive at this point, you really need to get with the times and live a little.
Check out the full detailed requirements here.