You want something (roughly, untested) like:
from multiprocessing import Pool
NUMBER_OF_PROCS = 5 # some number... not necessarily the number of cores due to I/O
pool = Pool(NUMBER_OF_PROCS)
for i in customerID:
pool.apply_async(getRecommendations, [i])
pool.close()
pool.join()
(this is assuming you only pass 'i' into getRecommendations, since the pickle.load should only be done once)