Linux's Cakewalk is called Rosegarden.
You can just go to Applications > Add/Remove > Sound&Video >
and install it. Linux audio is a trip however. If you're using a
Soundblaster Live!, then Google aound for how to get your
soundfonts loaded, If not, then you'll want Jack Control, and
qsynth (also in Add/Remove). The drill is, start jack, then qsynth
(with a sounfont) then Rosegarden.
I have a Delta44 playing real nice with Linux - the support is
out there, but the learning curve is pretty steep. If you intend
to do serious audio work in Linux, you should really re-install
over an ext2 filesystem, and write to a separate physical drive,
and have a LOT of ram...
Yes, I'm a musician - but that doesn't make me a recording
engineer! I'll be happy to help with what I've learned, so keep
us posted: threads like this are invaluable to the community.