http://www.celticguide.com/
Secondly, allow me to heartily to recommend the November 2012 edition of The Celtic Guide. The Nov 12 issue can be downloaded for free by clicking on the link above, scrolling down to the bottom of the page and then clicking on the front cover image - "Celtic Heroes":
http://www.celticguide.com/pdfs/nov12.pdf
This should open up a free PDF of the magazine.
Finally, allow me - if I may - to recommend the first article in the November issue. It's by yours truly and it represents a sort of potted guide to the death and burial of the first Arthur on record, Artuir mac Aedain, the original "King Arthur".
And, if you continue through this excellent magazine (a fabulous range of stories and articles relating to Celtic matters, especially of the heroic variety), you will come to an advert created by the gifted team at The History Press:
It's so good to have this level of support!