Many travelers want to use their vacation time to volunteer and make a difference. A new book, Frommer's 500 Places Where You Can Make a Difference , can help with that altruistic goal.

The $19.99 book by Andrew Mersmann offers travelers 500 service projects from around the world, most of which can be done in a one- or two-week span. They include teaching music at a girls' rock camp in Texas, protecting gray whales in British Columbia, restoring a Buddhist monastery in Nepal, or assisting at a refugee camp in Kenya.

The book offers tips on:

» How to decide what type of volunteer vacation is best for you.

» Discounts and perks offered by hotels as a reward for your volunteer work.

» Volunteer vacation opportunities in the United States and abroad.

» Family-friendly trips that will open your children's eyes to the world.

» Unique and lesser known volunteer experiences such as the Homeless World Cup Soccer Tournament, becoming a ranch volunteer, or bringing circus arts to at-risk youth.

» Celebrity-inspired vacations such as Richard Gere's Heroes Project in India or Paul Newman's The Hole in the Wall Gang camps for children with serious medical conditions.