well i use torrents to download my movies. I usually download from demonoid com but there are other sites for torrents like isohunt etc.. that have great collection of hi quality movies. To download torrents, you are going to need a client such as bittorrent, utorrent, bitlord....i personally like and use bitlord as my client to download torrents.
For ripping them...i have Nero - i have no problem with nero. Just make sure you get the full version of nero that has nero recode which is fit your downloaded dvd/movie onto 1 dvd disc. You can download Nero at torrent sites also.
It also doesn't matter if you have mac or pc...torrents/programs are made for both nowadays ;)