First we need to know which one of the 9 different models of MacBook you have. To see which model you have go to the Apple in the upper left corner and select About This Mac, then click on More Info (and then System Report if you’re running 10.7 Lion). When System Profiler comes up check the Model Identifier and post it back here.
The Late 2008 model 5,1 Aluminum Unibody and the Late 2009 model 6,1 and Mid 2010 model 7,1 White Unibody have a Mini DisplayPort. The Early 2006 model 1,1 through Early 2008 model 4,1s plus the Early and Mid 2009 model 5,2s have Mini-DVI ports. Each would take a different adapter to connect with the TV.
And also what input plug you'll be using on your TV. VGA, DVI, Composite or HDMI. (Composite is the red, white and yellow RCA plugs on your TV or red, white and S-Video plugs.)
To be more specific you need to specify your video connection (e.g., mini-DVI, DVI, mini-displayport/thunderbolt, etc.). Whatever it is, call it X, you will need a X-to-HDMI adapter and and HDMI cable (I'm also assuming your TV has an HDMI input). So, for example, if you have mini-displayport, you need at mini-displayport -to-HDMI adapter.
Let's assume you have a mini-displayport/thunderbolt to HDMI adapter and of course a HDMI cable.
Set the TV to the input you connected the HDMI cable to.
On your computer, if you open the Displays preferences and do not see an Arrangement tab (or there is an Arrangement tab that shows only a single monitor) then there is something physically wrong with your connection. Try clicking Detect Displays just to see if the computer can now sense the presence of the connection. Check your cables and make sure the mini-displayport plug is pushed firmly in so that essentially all the metal part disappears inside the socket. Mini-displayport plugs can be a little tricky in that you need to make sure the plug is fully seated in their socket.
If you do have an Arrangement tab, and it shows two screens, then click Gather Windows to bring the TV's Displays preferences on to your main screen if the TV is not yet showing an image. Set the proper resolution (probably 720p, 1080i, or 1080p). Set the refresh rate (probably 60Hz) if that preference is shown. You should see a picture at this point. I recommend turning off mirrored displays if it is enabled.
You may have to play with the underscan/overscan settings on your TV and the displays prefs for the TV if the picture is too small or larger for the TV screen.
Also, you need to set your Sound preferences to output to the HDMI connection. If the MBP doesn't support audio through the mini-displayport then you will need to connect your stereo audio out to your TV (3.5 mm stereo jack for the compter to usually RCA jacks on the TV).
And if running Lion, do not run in Lion full screen mode.