A recent question from a colleague:
"…we just went over the Camera Raw plug in. We did some custom settings that we saved, and a student was wondering if you can import the Adobe Camera Raw setting in to Lightroom?"
If your versions of Lightroom and ACR are in sync with regard to the camera raw version you can use the same presets for both. Find the ACR preset on disk and copy/paste it to the LR Develop presets folder. You will have to restart LR for the preset to show up.
Another way to approach this would be to make your changes in ACR, apply the desired settings to the photo, then save out the metadata (either as a sidecar or into a DNG). Then import the file into LR; the settings for that photo will carry over. Then you can save a Develop preset using the settings from that file.