It is a matter of personal preference, but if you care what I think, self-attunement seems to be useful as a temporary measure while you wait to have the opportunity to receive attunement from another person. It does work, but it always seems a little unsatisfying to me in comparison.
Usui Reiki is a requirement for many other types of reiki out there, and it offers a structure that Kundalini Reiki does not. It is a very good way to begin your practice if you intend to actually keep using reiki long term.
Ole Gabrielsen has Kundalini Reiki 2009 out now, which is an improvement on Kundalini Reiki 2008. The 2008 version consolidated the original 9 levels into 3 levels, so that the "booster" levels were no longer separate. A lot of the documentation out there on self-attunement refers to the original levels 1-9 of the original version.
You don't have to wait to start reading manuals.
http://www.theholisticcare.com/manuals.htm
It will still take several months to receive the attunements through the official requests threads, and if you can give yourself daily hands on self-healings that would be very useful. You don't have to wait for your first attunement from here to start with activating the Kundalini Reiki level you self-attuned to. In order to make sure I get a daily self-healing in even now, I just activate one of my reiki systems when I get ready to go to sleep at night.