2 question ’bout XP

1. In the introduction article about Windows XP there is a very interesting chapter about running application in the secure enviroment(like Java-applets in browser – but not this one!)Here it is”Provide administrators a policy-driven mechanism to identify software running in their environment and control its ability to execute. This facility can be used in virus and Trojan horse prevention and software lockdown.”
url=http://www.microsoft.com/windowsxp/pro/evaluation/features.asp#productive
Can anyone describe what does it mean ?
2. How I can share modem from another computer (both running Windows XP) in LAN (not using Remote Desktop Connection)?