Software download: http://www.linear.com/designtools/software/#LTspice

• Switcher CAD 3 manual, the last official manual by Linear Technology of the LTSpice IV predecessor.

• Short intro http://ltwiki.org/files/LTspice_guide.pdf

• Great tutorial by Gunthard Kraus, e.g. lossy transmission lines, S-parameters, filters, …

• RF Special Edition: Complete Simulation of a 137MHz Weather Satellite Converter using LTspice IV by Gunthard Kraus

• Tspice IV Getting Started Guide, Linear Technology presentation

• Undocumented LTspice

• Simulating Ideal Opamp (pdf)

• LTwiki: Courseware and Tutorials