Wow, PS4? That was the first version of Photoshop that I ever used, and that was back in 1997. Are you sure you don't mean CS4? []


Kidding aside, the biggest factors in color are ACR version and camera profile. The only way to get the same ACR version as LR3 would be to upgrade to CS5, but you should at least be able to set a similar camera profile (e.g. "Adobe Standard"), unless you are using the DNG file workaround for an unsupported camera, in which case you may not even be able to get that close. Of course, don't forget any of the obvious things like white balance, tint, tone curve, etc.