> Where do i go to find out how to pronounce ON?

there are two ways to pronounce Old Norse: you can use the reconstruction of
the ancient pronunciation, or you can read according to the modern Icelandic
sounds (which is more practical: there are many living Icelanders...).
I think the best thing you can do is to read mr. þorgeirsson excellent
explanation at

www.hi.is/~haukurth/norse/articles/pronunc.html
and
www.hi.is/~haukurth/norse/articles/altpron.html

If you prefer going further with modern Icelandic pronunciation, I suggest (and
hope everyone agrees) to buy a modern Icelandic coursebook with cassettes/cds
(I find it very useful in learning ON; the best book is "Colloquial Icelandic"
by Routledge. it's not cheap, but excellent). for the now you can see also:

http://www.omniglot.com/writing/icelandic.htm

Good Luck!

Diego