The site, www.how2fundraise.org, is funded by the Office of the Third Sector and the Vodafone UK Foundation. It provides advice on fundraising law and best practice, and allows volunteers to create sponsorship forms, letters and other materials bearing the logo and mission statement of their chosen charity.
Charities that are members of the institute can upload their logos and text about what they do to the site. When a volunteer selects a charity, it will appear on every page of the site once they have logged in. Any promotional fundraising material printed by the volunteer will then bear the charity's logo and text.
The site also provides events calendars, a step-by-step guide to running fundraising events, fundraising forums where volunteers can share ideas and guidance on fundraising law and best practice.
BBC Children in Need, Barclays, Marie Curie Cancer care and Volunteering England have already signed up to use the site.
"Volunteers raise billions for charity each year," said Lindsay Boswell, chief executive of the institute. "If we can help them raise even a few percent more, then that will be a massive additional contribution to good causes."