Free software to split or convert an AIFF file?

I found a program that works! It can be found at: http://www.nch.com.au/switch/index.html It took about 10 seconds to install and less than 5 min to convert the huge file and it's really simple to use. Highly recommend for anyone who finds themselves in the same boat at some point and closing this question now.

Just a warning for future readers that nch software apparently has a...mixed reputation. Here's http://superuser.com/questions/99492/is-software-from-nch-software-safe. The bad practices may be limited to installing extra toolbars, adware, etc., if you're not careful to seek out and uncheck boxes during installation (possibly hidden behind an initial "custom install" choice), but extra sketchy are the reports of being unable to easily uninstall this stuff once put into place. (It's also possible that a lot of the mistrust is due to their website suggesting the software is free, but most of it really just being 14 or 30 day free trials?) It's probably mostly harmless, but I'd suggest for future readers that the better solution would probably be to use Audacity. (http://manual.audacityteam.org/o/man/faq_installation_and_plug_ins.html#lame needs to be separately installed for Audacity to be able to export MP3s.) (Incidentally, it looks like at least one person reported Audicity no longer working on their computer after installing some of nch's audio tools. But I bet reinstalling Audacity would fix that up.)

http://www.erightsoft.com/SUPER.html will convert it to MP3 for free. If you can get over the website that looked dated in 1999 and the fact that it has the world's clunkiest UI, SUPER is amazing. It'll basically convert anything to anything else, and it's 100% free (it's a simple graphic wrapper over a bunch of powerful open-source command-line audio tools). (This is if you're on Windows, SUPER is windows only. For macs, +1ing Handbrake)

iTunes should be able to convert as well.

Doesn't https://handbrake.fr/downloads.php work?

you might even try this on your phone with a free ringtone editor

Chocolcate Pickle, Handbrake did not have an option for this file type. O9scar, I have audacity and didn't even thing to use it, but I just tried it and it said it needs some sort of (.dll or something) file to be able to convert and save. I just have the AIFF file. Any advice? Itaxpica, it doesn't look like SUPER works with AIFF off of what's on their website, should I just download and try it? (the download seems complicated)

http://sox.sourceforge.net/ + http://www.mpg123.de/ would probably be able to accomplish what you want. Have sox convert the aiff to wav and pipe that to mpg123 to convert to mp3.