Cover for the first issue of Hugo Gernsback's Amazing Stories, April 1926, by Frank R. Paul, illustrating Wells's In the Days of the Comet. Digital copies of this and many other early issues can be found at http://archive.org/
The Division of Rare & Manuscript Collections (RMC) in Kroch Library holds an archive of 76 science fiction magazine titles published from 1946 through 2006, including Analog, Magazine of Fantasy and Science Fiction, Astounding, Isaac Asimov's Science Fiction, Galaxy, Startling Stories, and others. The Finding Aid provides a list of issues.
RMC also has issues from the first four years (1926-1929) of Amazing Stories, the earliest U.S. fiction magazine devoted exclusively to SF, as well as a collection of materials related to Philip K. Dick's Do Androids Dream of Electric Sheep?
Garrett P. Serviss, pioneering SF author,
Cornell Class of 1872 and writer of Edison's Conquest of Mars, an "unauthorized sequel" to Wells's The War of the Worlds, as well as several other SF novels.