These web pages and this software was demonstrated in class.
Spherical Geometry Demo, by John Sullivan, U. of Illinois, is a Java applet that demonstrates parallel transport and holonomy.
The Geometry of the Sphere by John Polking, Rice U., recounts the geometry of Girard's theorem, the relationship between angle sum of triangles and spherical area.
Kaleidotiles, by Jeff Weeks, has a download site linked from this page at the Geometry Center.
This is just a sample. Look for spherical geometry or some special terminology in spherical geometry using search engines such as Google or Metacrawler.
The home page of David Henderson, the author of our textbook, has a link to his bibliography of geometry books and some information about the text..
This course on Celestial Mechanics at the University of Sheffield has a chapter on Spherical Geometry, with topics:i. introduction ii. the geometry of the sphere iii. spherical trigonometry iv. position on the earth's surface v. example problems.
This page of Dave Rusin at Northern Illinois University has a number of practical methods for computing on the sphere.
The spherical Pythagorean Theorem is explained on this page at Harvey Mudd College.
The Math Forum is probably the best web math resource, including a page of links on Elliptical and Spherical Geometry. (By the way, Elliptical geometry is not geometry on an ellipsoid, it is a version of spherical geometry where a pair of opposite points counts as one point, so then two great circles intersect in one "point".)
A very good source for the geometry of cartography is the Cartography document of John Polking (in Adobe Acrobar format). Another page at Rice by high school teacher Cynthia Lanius brings together recourses for K12 students; the main page for this map site is at this link.
This site at U. Alberta has some history and a number of interesting references and a page with an interactive Java applet.
This page at UBC has some interesting figures. A history of math page at SFU has a summary of dates and accomplishments of mapmakers of the 1500s and other times.
This Ask Dr. Math page explains how to map a point on the plane back to the sphere via Mercator projection.
A fascinating Java applet showing Stereographic projection is on a page of John Sullivan at UIUC.
This site of Hans Havlicek has an extensive gallery of maps of the earth by various projections. The Map Projection Overview of Peter Dana also has an interesting gallery.
Non-Euclid is an interactive program to explore the Poincaré disk model.
Cinderella is a commercial program that models Euclidean, spherical (elliptical) and hyperbolic geometry. A free demo version can be downloaded, or it can be purchased from Springer-Verlag.