myz. Honestly it's no hassle. Of the 90 sites i host, around 80 of those are hosted for free with no catch whatsoever (ok, except maybe for the "no illegal/adult stuff allowed". They're no ordinary sites either, i normally scout the net for people who have passion for the 'net - especially in design - and offer them hosting. At one time or the other i've also offered free hosting to student groups, non-profit consumer organizations and kids with disabilities. So no, it's no hassle at all. In fact i enjoy doing it. Gives me a warm fuzzy feeling inside
as for pure DNS info, specify the server info of your host and for the A records (if you have access to that) specify the one for your current site. If your current site doesn't have a unique IP assigned to it (and i'm pretty sure it doesn't) then use CNAME records and alias yourdomain.com to your geocities.com addy.