XOSL is a graphical boot manager that supports multi-booting of various operating systems. Development is currently done under the XOSL2 title. Historical version download below:
Xosl is wonderful! Thanks.
I don't know how well any particular version works (yet), but what I've read elsewhere sounds good (apart from this being more or less abandoned). Note however, that the www.XOSL2.com link given here is dead, the current official site is supposedly http://www2.arnes.si/~fkomar/xosl.org/home.html