The Immigrant Ships Transcribers Guild (ISTG) is apparently a volunteer organization that is systematically transcribing passenger lists from immigrant ships and making them available on the internet.

ISTG has been voted one of the top 25 Genealogical websites, as listed in the new February, 2005 issue of Family Tree Magazine. What makes this an extra special award is the fact that the readers voted for their top sites. To find out more go to Family Tree Magazine
The 25 sites are listed in alphabetical order and this is what they say about ISTG -
"This is one of the most comprehensive sites for locating immigration-related materials. Formed in 1998, the guild relies on a team of volunteers who decipher and transcribe ships' passenger lists,then makes them available to anyone with Internet access. Read the excellent search tutorial, then scour the site for your immigrant ancestors. Take time to mine the bounty of resources on this site, including ship images, marritime routes, maps and dozens of links to other immigration sites." 

In the March/April 2005 issue of the AARP magazine, page 84, under Resources, Immigration Info, ISTG was mentioned along with "The Olive Tree" and Ellis Island as resources for immigration information if you are doing genealogy research. The article - Trace Your Family Tree By Richard Rubin contains "expert advice on finding your ancestors without losing your mind"