updating active directory user profiles with.net

hi all; i'am using this forum first time. i like this very much. i have a questions abut active directory with .net. so i wanna updating user profiles using asp.net. for example there is a computer laboratuar , a windows 2003 server and a web page that using active directory accounts to authenticate system. for example me. i wanna updating my profile using web page , if i authenticated system. i hope, i can tell my questions:) 'cause my english not good. thanks.