The SBS 2003 Action Pack versions are Not-For-Resale and Not-For-Distribution, so they can't be sold or given away and, if the annual licensing fee is not paid, they must be uninstalled. They are for business use, training, and demonstration by the Action Pack licensee. You can read all the licensing details on the MS Partner pages on Microsoft's site.
Their EULA gives the other license terms, which are the standard SBS terms.
They come with 5 built-in licenses and there's a certificate in the Action Pack for five addtiional licenses.