ComBat is now available in the SVA package in the Bioconductor project. We have moved all ComBat questions to the Bioconductor mailing list: bioconductor@r-project.org. Please send ComBat questions and comments there. For a quicker response please start your subject line with "ComBat:" and you are welcome to cc me (wej@bu.edu) or mention us on Twitter (@wejlab) and I will respond to the thread as soon as I can.
Also, the original R script is still available, but we will not be supporting this version any longer. You can download it by clicking here, and then pasting the code into a text editor. Name this file 'ComBat.R'.
Please check the 'Usage' page to get help on what to do with this R script!