That depends on your mathematical background and the level of abstraction you want.

If you need a little background in topology, very good and short books on general topology are **Runde**'s "*A Taste of Topology*" for a more formal approach and **Jänich**'s "*Topology*" for a more didactic and graphical-reasoned introduction. Then the approach to manifolds from pure differential topology could be started by **Jänich** - "*Introduction to Differential Topology*" which is very graphical, short enough and quick to the point to master fully.

But if you are really interested in these matters from a theoretical physics perspective, you should by all means read the book by **Nakahara** - "*[Geometry, Topology and Physics][1]*"; there you can read a very thorough introduction (although sometimes concise) to most of the topics of differential geometry and topology of interests for physics: homology and homotopy groups, calculus on manifolds, Riemannian geometry, complex geometry, fiber bundles, connections, characteristic classes, index theorems with applications. It is a wonderful book if you have enough background and use supplementary readings (for example in tensor, multilinear, algebra). Other similar book with the same spirit are **Frankel**'s "*The Geometry of Physics*" which is longer dealing with most of the same contents more, nevertheless I do not find it as useful and straight to the point as Nakahara's (and Frankel's notation is not the most orthodox standard).
Similarly, I recommend the new book by **Eschrig** - "*[Topology and Geometry for Physics][2]*" which again deals with the same content as Nakahara's but with a less mathematical exposition (definition, theorem, proof...) since it is written to be read as lectures or a physics text. Nevertheless is detailed, uses many figures and develops the same amount of detail or more.
This kind of books develop the necessary topological background all along as needed.

For a more mathematical purely formal treatment of differential geometry on manifolds I would dive in the wonderful book by **Nicolaescu** - "*[Lectures on the Geometry of Manifolds][3]*" since it is very complete and modern. Another slower mathematical exposition is **Jeffrey Lee**'s "*Manifolds and Differential Geometry*" which may be useful to you as a companion to the other physics-oriented texts, since it develops many details and background at some points. They are both wonderful books in my opinion.

For an approach to manifolds through mechanics, the classic book of **V.I. Arnol'd** - "*Mathematical Methods of Classical Mechanics*" is wonderful but it is very applied and focused on symplectic geometry (and despite being a masterpiece, it is a little bit out-dated in style for my tastes). Another differential-geometric introduction to mechanics is **José/Saletan**'s "*Classical Dynamics: A contemporary approach*". The most advanced book of this kind is the bible by **Marsden/Abraham** - "*[Foundations of Mechanics][4]*" which I think is a masterpiece trying to developping the complete theory of mechanics from a purely differential-geometric perspective.

My personal advise would be to read Eschrig alongside Nakahara, that is what I did with a background on theoretical physics. Then you should consult some of the other books to fill particular gaps and needed background.

This is a wonderful and very interesting subject, good luck!


  [1]: http://www.amazon.com/Geometry-Topology-Physics-Graduate-Student/dp/0750306068/ref=sr_1_1?ie=UTF8&qid=1302464475&sr=8-1
  [2]: http://www.amazon.com/Topology-Geometry-Physics-Lecture-Notes/dp/3642146996/ref=sr_1_1?ie=UTF8&s=books&qid=1302464501&sr=8-1
  [3]: http://www.amazon.com/Lectures-Geometry-Manifolds-Liviu-Nicolaescu/dp/9812778624/ref=sr_1_2_title_1_p?s=books&ie=UTF8&qid=1302464546&sr=1-2
  [4]: http://www.amazon.com/Foundations-Mechanics-AMS-Chelsea-Publishing/dp/0821844385/ref=sr_1_1?ie=UTF8&s=books&qid=1302464574&sr=1-1