iChat/skype broadband usage

[jeevescat]

I'm trying to kit out the in laws with a suitable broadband line so that little JC can say goodnight to granny in Australia over the net, we mainly use iChat, sometimes Skype. How much bandwidth do these video links use, can get a reasonable deal on a 1gig/month limit, but nit sure that is going to be enough? The speed will be about 1.5mbs.

Any ideas?