uridium said:Cant EVER see a Sony device being AAC compatible, Apple and Sony are Arch rivals as far as portable music goes. Sony's own format (and massivly better with it) is Atrac. Rumours are of a firmware upgrade due soon to make the Sony Walkman phone range Atrac compatible.
Safest bet is always to rip your music as MP3 as any device will always play this.
cwick said:Pretty much everywhere I've looked says that the W800i supports AAC. Just check google.
The PSP supports AAC too - so it's not like Sony are anti-AAC (it's just MPEG4, which is an industry standard).
It may be that the w800i, like the PSP, needs the iTunes files to be renamed from .m4a to .mp4 before it will recognize them though.