Good undergraduate level book on Cyclotomic fields

I would just start by looking at Marcus' Number Fields for the basic algebraic number theory. It also contains tons of exercises. If you read the first 4 chapters, you should have the necessary background for most of Washington's book. I'm not familiar with Lang.

I started studying algebraic number theory last summer by going through Marcus book.

pki's suggestion is good. A couple of other books worth a look are Pollard and Diamond, The Theory of Algebraic Numbers (in the MAA Carus Mathematical Monographs series), and Stewart and Tall, Algebraic Number Theory. Ireland and Rosen, A Classical Introduction to Modern Number Theory, doesn't get as far into algebraic number theory as the others, but it is well-written and has a chapter on cyclotomic fields and a chapter on Bernoulli numbers.