Been away for a while and just catching up with older threads, saw this.
Hard for me to answer that when there are so many takes on Reiki, so I thought I'd post some of the better known sites, where anyone can browse and learn more.
There are lots of different Reiki traditions - some you get 'attuned' to, others based on older, Japanese practice, do something called 'reiju', some call it 'empowerment'. They all come to the same thing.
Attunement/reiju whatever you want to call it, only takes quarter of an hour or so. But for the different levels of Reiki, you have to learn and assimilate information. Well, nothing much for level 1 which is enough to help you Reiki yourself and maybe your immediate family. But in Reiki II and III you have to learn the symbols and sometimes background material. I also read a little about buddhism, as I felt it would be disrespectful to get into Reiki without understanding a very little, at least, of the culture from which it came.
There is a lot of secrecy around reiju/attunement. Some Reiki people believe in giving out info even to non Reiki people, others don't. This reticence isn't for cultish, sinister reasons - there are valid reasons for it. Since the 1980s, the symbols have been in print and can be tracked down by anyone. So it's hard to decide how much to say, re. attunement.
What is already well known is that during reiju/attunement, the Master 'passes' the symbols to the student, places them on them, so to speak. There are as many different ways to do that as there are Reiki Masters.
My first attunement was from a friend and it was in a form of what I now know to be 'Western' Reiki. I since studied a more Japanese style Reiki with these people and although they do distance Reiki reijus, I went to one of their 'in person' courses. Even if not in the UK, the site is interesting and will tell you more about reiki than I could here:
http://www.reiki-evolution.co.uk/
They are unusual in that they send out course materials ahead of the actual day of attunement, so you can get familiar with it all and on the day, just relax.
Some other reiki masters do that. Others, expect you to learn the symbols on the day if doing Level II and there used to even be a rule that you couldn't carry representations of them with you out of the room, so there'd be no chance of non Reiki people seeing them. Again, this isn't sinister - it's a cultural thing, a feeling the symbols work less well for someone who has seen them before attunement.
These Aussie people have written what I think are the best books on Reiki - they have disentangled a lot of its history and also de-bunked some of the New Age western claptrap that it attracts.
http://reiki.net.au/
(Chakras, for example, are a late and Western introduction - nothing to do with Japanese Reiki, as chakras are an Indian concept, not a Japanese one).
I'd read Bronwen and Frans Stiene's 'The Reiki Sourcebook' if you are thinking of doing Reiki, because then you can choose a style of Reiki that suits you. I like a stripped down, fairly instinctual version, closer to the early one. Many other people like the New Age stuff better. Both work. Reiki has had hundreds of offshoots and some people are very dogmatic that 'their' Reiki is the only true one.
If you explore articles on the Steines' site it might clarify a few things!
This gentleman is also very well known in Reiki circles, worldwide:
http://www.reiki.org/
As is this gent:
http://www.reikidharma.com/