I installed the beta2 camera profiles for PS CS4. Camera Raw 5.6. When I go to the dropdown box in the Camera Profile presets there is only listing for nikon D2x profiles and Camera Standard, Portrait, Neutral, and Vivid. I have a D300. Should there be profiles for other cameras other than the Nikon D2x? If Yes how do I import them or where can I find them. Are there profiles for the d300?
The profiles that don't say a camera are for the current camera which is a D300 in your case. The D2x ones simulate that camera mode on the D300.
I think the D300 is new enough not to be supported by the old, old beta profiles, but they will clutter up the list for older cameras, so it's better not to have installed them. ACR 5.6 comes with its own up-to-date list of profiles.