I've found the Ubuntu Studio realtime kernel to work quite well.  I'm running Jack + pd and getting a stable 8ms latency with a Roland UA-25 usb soundcard ... and this is on both a Pentium M thinkpad and a P3 Celeron 500 with some of the hoggier services disabled.
<br><br>I just use the regular Ubuntu dektop distro and installed the realtime kernel image ... all of the UbuntuStudio apps are available to regular Ubuntu (my laptop) as well as Xubuntu (xfce for the slow, little computer).
<br><br>So yeah, works great for me.<br clear="all"><br>-- <br>Dan Wilcox<br>danomatika<br><a href="http://www.robotcowboy.com">www.robotcowboy.com</a>