The Tree of Life web project (ToL) can be accessed at http://tolweb.org/tree/phylogeny.html.

From the “about” page on the web site:

The Tree of Life Web Project is a collection of information about biodiversity compiled collaboratively by hundreds of expert and amateur contributors. Its goal is to contain a page with pictures, text, and other information for every species and for each group of organisms, living or extinct. Connections between Tree of Life web pages follow phylogenetic branching patterns between groups of organisms, so visitors can browse the hierarchy of life and learn about phylogeny and evolution as well as the characteristics of individual groups.

For background information about the Tree of Life Web Project, see this article in the special issue of the journal Zootaxa, Linnaeus Tercentenary: Progress in Invertebrate Taxonomy:

Maddison, D. R., K.-S. Schulz, and W. P. Maddison. 2007. The Tree of Life Web Project. Pages 19-40 in: Zhang, Z.-Q. & Shear, W.A., eds. Linnaeus Tercentenary: Progress in Invertebrate Taxonomy. Zootaxa 1668:1-766. Open Access: Abstract (PDF; 20KB) | Full article (PDF; 830KB)