In OS X Lion, when I launch a new tab in the Terminal with Cmd+T, the shell starts in the
$ pwd /
Usually how the new tab is opened relies on the settings in terminal.
The New tabs open with: setting should read however you would like the default behavior to be. I'm guessing you should switch this to Default Working Directory (opposite of what I have selected below).
If you're having issues where you want the same directory that you're working in to open, you may need to adjust some of your terminal environmental settings.