If your tapes are from your camcorder and this is digital then you need a firewire cable plus a compatible graphics card. If the tapes are analogue (VHS etc) then you will need specialist software and probably hardware. I use Pinnacle Studio 400 but there are lots of others.
If you are going to transfer tapes to youtr hard drive you will need a very big drive as the files take up a lot of room.
To write to DVD you will need a DVD burner which is very expensive.