There are several ways to install the SCCM client. As you know, it may be installed during OSD using a package, or the built-in push feature after discovery, but sometimes it might come handy to be able to install it using a script. (More about Client Deployment here: http://technet.microsoft.com/en-us/library/gg682132.aspx)
Nothing really fancy, just a plain .bat file containing following information:
“\\SITESERVER\SMS_SITECODE\Client\ccmsetup.exe” /mp:FULLY QUIALIFIED SERVERNAME SMSSITECODE=SITECODE
Replace everything in bold with your own details.