Wikimedia
Wikipedia: Hyperbolic Geometry
This encyclopedia entry from Wikipedia offers a discussion on hyperbolic geometry. The site explains how the hyperbolic geometry plane is represented in two dimensions and how lines in the plane must be drawn. Other types of models for...
Wolfram Research
Wolfram Math World: Hyperbolic Geometry
Hyperbolic Geometry is discussed here with specifics on the lines in this geometry. The equations of the lines are represented as well as a desription of the lines. The site has links to other non-Euclidean Geometries.