first, what magic are you wanting to learn? second online or offline?
if you have an ocult shop near you, you can always look through there. Element Encyclopaedia 5000 Spells and Pure Magic: A Complete Course in Spellcasting both by Judika Illes would be good. i have a few of her books and i love them.
also found it on google books http://books.google.ca/books?id=AzPtWdpG-9MC&printsec=frontcover&dq=Pure+Magic:+A+Complete+Course+in+Spellcasting&source=bl&ots=nUFpEvrNK2&sig=pD2kAkub9wCbw_n_cNIt3SeQhKo&hl=en&sa=X&ei=XuxJUIanBYbH0AGgmIGICQ&ved=0CDMQ6AEwAA#v=onepage&q=Pure%20Magic%3A%20A%20Complete%20Course%20in%20Spellcasting&f=false