According to my copy of the documentation, the NSXMLParser
class is available on Mac OS X 10.3 and later.
If for some reason you cannot use that, you can also use the Core Foundation XML Parser functions (search for CFXMLParser
). This is a C-based API also developed by Apple. It will be deprecated in future versions of Mac OS X (after Snow Leopard), but since you're working on 10.3 that won't be a concern for you.
Many who cannot use those two also use libxml. Objective-C is able to use any C-based libraries with no penalty. I'm fairly certain Mac OS X ships with a copy of libxml you can link to (no need to download, build, or ship the library yourself; though if you want to, you certainly can).
What's best is going to depend on what features you need. Namespaces, for example, aren't fully supported by NSXMLParser in 10.3, but they are supported in 10.4.