I went to Kibbutz Yahel for Harvest in 2005 and stayed to December. The experience it self was truly unforgettable - made great friends, learnt a language, really tried to immerse myself in the culture (there is even romance in the air on occasions).
Its NOT all roses. Trying to get a place in a good kib is a nightmare - the ones that want volunteers arent the nice agricultural ones but rather the ones that have toilet roll facotries. The stupid organisation that allocations no longer operates in Golders green to get placements (although it sometimes still claims 2) so you`ll have to go to the Tel Aviv office - this measn a lottery to where you end up.
hope i was little helpful.
Will
p.s My mate went to Hazorea and loved it
Did he just volunteer there or did he do the ulpan?