Sorry for the delay in responding.
We had a Q&A session on this forum on speech and language problems in Parkinson's. You can find this here: http://bit.ly/O23nAB
In the session, the expert discussed the Lee Silverman voice training and they have a range of products including DVDs. You can find the site on the Q&A page or here: http://www.lsvtglobal.com
I hope that helps.