Hi Simon,
I also have difficulty with that, because I only have the Zoëga
from 1942, and the word isn't listed there. I have noted
that the word "forsala" is used a lot in modern Icelandic.
For example: (from the internet)

» Miðaverð á árshátíðina er eftirfarandi:
Skemmtiatriði, kaffiveitingar og dansleikur
1500 kr.
Kaffiveitingar og dansleikur fyrir nemendur
skólans 750 kr.

Ef fleiri en tveir nemendur eru frá sama heimili er frítt frá og með
þriðja barni.

Börn undir grunnskólaaldri fá frítt inn á árshátíðina. Forsala á
miðum verður í húsnæði Grunnskólans á Hvammstanga fimmtudaginn kl.
8:30-16 og föstudaginn kl. 8:30-14.
Nemendur sem taka þátt í skemmtiatriðum þurfa að vera mættir um kl.
20:00
«

And so I definitely think it has something to do with selling.
Probably ticket sales for the described social event.

I did however find the meaning of "hafin".
That derives from the verb "hefja", which means 'to begin'.
Like the corresponding English (begin, began, begun),
"hafinn" is like 'begun'. But when the 'something'
that is begun is of the female gender, one n has
to be dropped. And so it is 'hafin' with only one 'n'.
Hence 'forsala' should be of female gender.
('hafinn' goes like the adjective 'heiðinn')

From the web page, I read something to the following effect:
"The well known and authoritative dictionary of
Icelandic by Arni Böðvarsson is now in a new edition
(the third), and compared to the 1983 edition, it has
been much expanded with many new words and explanations.
(600 pages more than in the '83 edition)
It now comes in two volumes, to replace the old
one-volume edition. It will be ready in november."

Personally I find it a bit hard to work with, because
I am not able to read Icelandic very fluently. But
for those who do, OHO! I think this is THE dictionary
to use. (the edition I have is similar to Webster's
with many illustrations in b/w)

Best
Xigung.

--- In norse_course@yahoogroups.com, simonfittonbrown@... wrote:
> Hi!
>
> Pls could someone translate and/or explain the meaning of the
aboves
> sentence?
>
> The web page I found it on:
>
> http://www.edda.is/frontpage.asp?cat_id=232
>
> Cheers, Simon