Cosmic Strings and other Defects  
   A series of articles on topological defects in the universe
   http://www.damtp.cam.ac.uk/user/gr/public/cs_home.html

Topological Defects in Cosmology  
   A review by Ajit M. Srivastava of various topological defects in particle theoryu models of the early universe (in PDF format).
   http://www.iisc.ernet.in/pramana/dec1999/c10.pdf

Topological Defects  
   This is an introductory set of lecture notes on topological defects, given to an audience with interests ranging from astronomy to particle physics.
   http://www.physics.adelaide.edu.au/mathphysics/abstracts/ADP-95-58-M40.html

Formation, Interaction and Observation of Topological Defects  
   A survey of defect distributions in first-order phase transitions, by Tanmay Vachaspati.
   http://arxiv.org/abs/astro-ph/9903362

Topological Defects and Cosmology  
   A review of the effects of defects in cosmology, by Robert H. Brandenberger.
   http://arxiv.org/abs/hep-ph/9806473

Cosmic Strings  
   A review by M.B. Hindmarsh and T.W.B. Kibble of the physics which predicts the properties of cosmic strings and topological defects.
   http://arxiv.org/abs/hep-ph/9411342