ok: you ask two questions:
a)which linux-distribution would you recommend for a low-specs PC
b)how do i manage my itouch.
about b i don't know, but i'm pretty sure that it doesn't relate to the linux-distribution you run. A short search on google (term "itouch and linux") doesn't look bad.
So that shouldn't be a big problem.
now back to a)
dsl is quite fast, but i am not sure if its still under development.
ubuntu is a very friendly linux-distribution, but i would say it is not what one would call low-specs friendly. If someone will say: use Xubuntu, its for low-specs PCs, i will say: that uses still much more ressources than, for example, dsl.
Damn Small Linux uses a window-manager called fluxbox. A window manager manages the way the windows are getting shown on the screen. Fluxbox is very fast, and so are other window-managers.
The small or low-specs linux-distributions usually use window-managers. Those small distributions
are, for example:
damn small linux
and much more.
The "full" distributions use desktop-environments.
A desktop environment comes with a) a window-manager b) a lot of apps, more than one needs and c) a lot of services running out of box (printing, bluetoes and what not).
There are four of them:
Gnome and Kde are the most popular ones and they offer the most comfort.
LXDE and XFCE are not that popular, but still quite popular, and still offer a lot of comfort. They are a bit faster than the first mentioned ones.
All the four of them are very easy to use, as they come with all that you need and got a nice look and fell out of the box. Therfor they are slow.
To make a confusing situation more confusing:
you can install any window-manager
on top of a desktop-environment.
So: install any linux-distribution you are able to.I would avoid kde as an environment. After you have done that install a window-manager. When the login-screens comes up choose to boot into the window-manager instead of into the desktop-environmnent.
That way you got all the comfort of an environment and all the speed from a window manager.
About with which distro of linux you do that? It doesnt matter. Debian is a good one, as it doesnt come with that much services enabled after a fressh install. Others might be good for that too. Ubuntu ain't (for this special purpose).
Got it? here are the main terms: linux-distribution, desktop-environment, window-manager.
i hope this was of help.perhaps someone will have got better "tips" or ideas.
and linus72, a member of this board, has created different isos with all kind of window-managers. if you want to have a short look which one looks like what: