How can I get UserID of a logon User

Hi Guys,

I am currently implementing a dynamic site map on my Enterprise Portal version 6 SP 9. I am trying to create a site map such that every user that log on to the portal will see the object assigned to him.

My problem is that I want know the API or class to use to get the logon user ID.

I will appreciate you help.

Thanks.

Dakata A Ibrahim