Radio1 Colin and Edith interview Anthony Daniels and Dave Prowse - 2004
James Earl Jones general interview, Star Wars mentioned
Jeremy Bulloch BBC Wiltshire Interview
Michael 'Mr Bronson' Sheard BBC Wiltshire Interview
Dave Prowse BBC Wiltshire Interview
I've also got more recent, prequel related interviews. Radio1's Colin and Edith did a week of ROTS interviews from Cannes with Lucas, Hayden, Samuel L Jackson, Portman and McDiarmid if I remember correctly. Got all five shows on harddrive somewhere, but need to edit them down to just the interviews.
There's also Joe 'Adam and Joe Show' Cornish interviewing Rick McCallum. Haven't Listened or downloaded this yet, but heres the link.
Joe Cornish interviews Rick McCallum
And lastly, there's Mark Hamill talking Star Wars at the 2004 DVD release.
Article
Mp3 from above article - as their link doesn't work