Software Audit (Easy Points)

Does anyone know of any good software that will tell me what software is installed on a PC/network of PCs? We have a lot of customers that dont know what they have installed on all of their pcs and they want to regulate what is being put on PCs andalso to make sure there is no piracy on their network. If anyone knows of any good software that audits software, could you fill me in (product, company, website) Easy Points for a little info. Thanks in advance