1)VBA for dummies
and the other one I cant remember the exact name of, but it's Microsoft Press and is called something like
2)VBA Fundementals in Excel
The first of those does cover Excel XP, but the second is specifically for Excel 2000. I presume there now is an XP version?
Also, I have got a great deal of help from click here
And finally, I learnt a lot by recording macros and then studying the code generated. (Tools>Macro>Macros>Edit).