Any of John Walkenbach's power programming books - one for just about every
version of Excel, so I would assume you would want the latest.
Check out John's site
http://www.j-walk.com/ss/excel
should be a link to his books.
If you have some experience and are looking for more advanced features, you
might also want to look at John Green/Stephen Bullen/Rob Bovey/Robert
Rosenberg 's book
Excel 2002 VBA Programmers Reference (wrox press)
See Stephen's site
http://www.bmsltd.co.uk/