Summer is almost over, but if haven't done your summer reading yet, get started! Here is some material to catch up on.
I previously mentioned the final publication of the new Intro to IR book from Manning, et al. It will be a classic.
There is also background material for the MPhil in Computer Speech, Text and Internet Technology (CSTIT) from the CL at Cambridge.
An Introduction to linguistics by Ted Briscoe.
Background on basic maths: set theory and logic, linear algebra, and probability.
The main book for the one year course CSTIT course is Speech and Language Processing by Daniel Jurafsky and James Martin. A new second edition of the book was released this Spring. It's at the top of my reading list. The first edition was a classic and I'll try to write up a review of the second edition when I get through it.
If that doesn't keep you busy, there is always Moffat, Zobel, and Hawking's Recommended Reading for IR Research Students.