The basic concept is to enter the date of the live transmission and any search terms to narrow down related tweets. Do some tinkering to find the twitter search pages that cove the broadcast, then generate a new subtitle file '_prepared.xml'.
The broadcast you download from iPlayer will be stored in a folder (something like My Documents] > [My Videos] > [BBC iPlayer] > [repository] > [obscure-broadcast-folder-name- like-b00qx4t0]), locate this folder and replace the file which ends '_prepared.xml' with the one created by this tool keeping the obscure file name ie b00qx4t0_prepared.xml. When you replay the broadcast turn subtitles on to see the tweets. (Not all iPlayer programmes have a subtitle files. In this case in the obscure-broadcast-folder you will need to edit the file with the same name as the folder to include something like:
All tweets used in this tool are attributed to the original author. Source data used to generate twitter subtitles conforms to twitter's auto delete policy. If you are unhappy about your tweets being used as part of this tool please contact me and your tweets will not be used.
This tool can also be accessed via an API using POST or GET method.
If you haven't already guessed: This site is a third party application for Twitter | This work is licensed under a Creative Commons Attribution-ShareAlike 2.5 UK: Scotland License.