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I know both and I enjoyed this one more: http://www.ir.uwaterloo.ca/book/

Not a direct alternative, but "Foundations of Statistical Natural Language Processing" by Manning and Schuetze is of significantly higher quality, and explains many of the concepts you will need for information retrieval.

Also, "Speech and Language Processing" by Jurafsky and Martin is an excellent book.

http://infolab.stanford.edu/~backrub/google.html

For those that might pass by this link without clicking, it's worth noting that it's a paper by Sergey Brin and Larry Page titled "The Anatomy of a Large-Scale Hypertextual Web Search Engine."

Looks like a great read. Thanks for posting!