There is no office 2003 for mac it was a windows porgram, (win200,XP,Vista,7)
I would look at getting open office if you need to be cheap, if you need something that publisher\Word , as well as lots of keynoted get I-work, it Mixes with all of the I-life apps,
but I hope find what you want,
Openoffice.ca
Apple.com/Iwork
www.microsoft.com/mac/products/Office2008/default.mspx
But if you just need something very very basic, you should look at the built in Text edit, and it does have spell check. Windows never had that or will