Really? It is not working on my TiBook 400 (and Palm m100). I cannot sync via IrDA using the Palm desktop Beta. It's just not connecting. Even got a kernel panic (my first and only in 10.1).
So it might depend on the machines you're using.
Alexandert: yes, IrDA works fine with 10.1.2, I can connect to the net via my mobile phone using IrDA. But synching my palm just doesn't work. Since I don't have a USB cable for it I don't know if it works at all with my setup.
I really hope Palm gets some working software on the way soon.
Although I can hotsync my Sony Clie (Palm OS 4.1) with my TiBook 500, I find I can only do it once per boot. In other words, after I hotsync--or for that matter use my IrDA for any other purpose with my palm, like pppd--I have to reboot to use it again. Dunno why.