Here’s a GRUB2 configuration that will work with (at least) Ubuntu 10.04/Lucid.
I know this is more of an “end user” thing and the OS is still very developer-centric, but I figure it can’t hurt to start thinking about that kind of thing. 
#!/bin/sh
This file makes a good ‘/etc/grub.d/35_haiku’ (make sure it’s mode 0755)
Once this file is in place, run “sudo update-grub” to apply it to the actual
GRUB2 configuration file ‘/boot/grub/grub.cfg’ (and again after any edits)
echo “Adding Haiku menu entry” >&2
cat << EOF
menuentry “Haiku (Nightly r37221 gcc4hybrid) (/dev/sda5)” {
set root=(hd0,5)
chainloader +1
}
EOF
EOF
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