The newest version of in_cube (renamed to Stream Player) can play XA. However, it's not hosted on HCS's site yet, for a few reasons. For one, it hasn't been *thoroughly* tested (I'd say it's reasonably safe though), and I'm pretty sure the code is a mess. Apparently, there's also some licensing issues.
From the #usf logs:
[7:13] <FastElbJa> - fixed NPSF loop points & samples calculation [7:13] <FastElbJa> A total of 20 new formats supported : [7:13] <FastElbJa> - Add other PS2 ADPCM variants support [7:13] <FastElbJa> (CCC, FSB, FAG, MIB, MUSC, PSH, RWS, RXWS, SVAG, VPK, VS) [7:13] <FastElbJa> - Add PSX CD-XA support (no direct CD support, the file must be copied to hdd, and have the RIFF & CDXA header informations). [7:14] <FastElbJa> Actually, only the first channel found in the file is played, and the length calc could be wrong. [7:14] <FastElbJa> - Add XBOX ADPCM (WAV support) + others variants (WAVM, which is headerless, XMU, FSB & XMS) [7:14] <FastElbJa> - Add EA/XA support (Electronic Arts Sound Format). [7:14] <FastElbJa> - Add RAW ADPCM (RAW (headerless) & RAWX (with header)) & Native WAV Format. [7:14] <FastElbJa> enjoy :) [7:14] <FastElbJa> could still have some bug, and the code is a bit a mess :P [7:15] <FastElbJa> no more crash at it is compiled with vc6 [7:15] <FastElbJa> so info + config works [7:23] <FastElbJa> ohh, i renamed the plugin to Stream Player, as it handle more stuff than Cube
Note: I didn't provide a link here, due to the above reasons. If you really want it though, you can probably find it... Then again, after looking through Google, it *might* be a little difficult to find...
Here's an alternative - Snakemeat's tools. This is what most of the new formats in in_cube were ported from. The new in_cube is *really* nice. Hopefully the above issues can be dealt with quickly, so that the new version can be hosted here/replace the old one.
Sorry I couldn't be of more help, but hopefully this will at least be useful.
EDIT - D'oh! I forgot to mention that foobar2000 can play XA files. I don't remember if that's by default, or if that requires extra plugins, but I know that I've listened to XA files in foobar2000 before. Mouser X over and out.