It's not as easy as it sounds, since there is alot of information in an xls file, ofcourse there are different versions too. http://sc.openoffice.org/excelfileformat.pdf
Normally when you are a beginner looking at something like this, you would use CSV files, as they are much easier to read etc. Please note, we will not provide code solutions for you, you will need to do some work yourself and show evidence of the fact you have done so.
Chris