How to get info from active directory
Look for a user or group
This works on most windows machines (if they are connected to a domain):
Rundll32 dsquery.dll OpenQueryWindow
...brings up a tool that lets you search for users or groups. It does not tell you very much about the user or group, but you can see which users and groups are in a group.
Find out information about yourself
The Group Policy Result tool tells you interesting things, even if you're not connected to a domain.
gpresult /v
...including which groups you are a member of.
Find your logon server
In powershell:
echo $env:LOGONSERVER
(or in cmd.exe use echo %LOGONSERVER%)
Use Sysinternals tools
ADExplorer from sysinternals is a comprehensive tool for exploring the Active Directory environment.
You can use all of their tools without manually downloading them by using:
net use * \\live.sysinternals.com\tools\
...to create a local drive (e.g. z: from which you can access all their tools.
Remote Server Administration Tools
If possible though, I prefer to use RSAT (a name it is best not to say out loud) which includes 147 powerful powershell Cmdlets in an ActiveDirectory module. I mostly use Get-ADUser and Get-ADGoup.