Depending on where you are of course, there are often workshops for unaccompanied voices; there is one in Leeds later in May for example with Maggie Boyle.

Contact Yorkshire Dales Workshops (www.ydw.org.uk I think). Even if you are the other side of the world they are great people who will do their best to help, and of course there'll be links.... Festivals have this type of workshop as well.

Good luck
LN