beginning unix looks alright, not looked at it though.
Sam's
Teach yourself unix is a good start, looked at their book series previously and they seemed to cover the bases well enough.
Introduction to unix & linux by McGraw's Hill, good book, had a flick through it.
Unix System Administration Handbook (3rd ed) THIS is a great book, have it at home, worth paying the $104 for it, if i lost mine i'd happily fork out for another copy. Had a sysadmin i was working with in 2001 recommend it to me as he had the 2nd edition of it and i used it for ages before i bought my own copy of the 3rd edition.
Unix Bible (2nd ed) also got this at home, it's good, but not as good as a the s-a-h
UNIX Shells by Example (3rd ed) Got this at home too, its good for learning shell scripting once you've started to get the hang of working your way around a unix/linux system.