Retrieve data from AD from within a custom sharepoint 2010 webpart

Hi,

I have a requirement to retrieve user data from AD and display from within a custom built webpart.

I am using the PrincipalContext class etc to get the info from AD, i have sucesfully done this in a console program without having to specifiy a username/password.

In the webpart i have successfully retrieved the data by hard coding my domain username/password.

Any ideas what i could do to get the webpart to retrieve information from AD without having to specify username/password?

thanks cjm