The way I do it is using GrandPerspective (Open Source - http://grandperspectiv.sourceforge.net).
You first need to be able to see the Time Machine backups. The backups are in an sparser image that you need to mount with Disk Utility. The sparser file is called "MachineName.sparsebundle"
Once mounted you will see a new disk called "Time Machine Backups".
Start the application GrandPerspective and when asked for the folder or drive to scan, you select the folder with the last backup, this will look something like :
"Time Machine Backups/Backups.backupdb/MachineName/YYYY-MM-DD-HHMMSS"
To select the last backup you will need to select the folder with the closest date or sort by date of creation.
Once GrandPerspective has finished, you will see a graph showing pretty much the same than if you had scanned the hard drive that you backed up. The difference is that most of those files are hard links to previous versions. So you can asked GrandPerspective to filter all the Hard Links. To do that, select "Window/Filter…", then select the filter "No Hard Links" and press Ok.
You will now see a new GrandPerspective window with only the files that where backed up on that last backup.
Note that this instructions only work with the last backup as is the only one that the backed up files will not have any hard links.
If you want to analyse the whole time machine backups, then I recommend you to try the instructions given here: