Using an online whiteboard with pen tablets while talking over skype is the closest I've come to sitting around a piece of paper. I've done this with two other people simultaneously and it worked quite well.
Unfortunately everyone needs additional hardware for this setup to be fun, but the cheapest pen tablets (from Wacom e.g.) are at about 70$ and are quite easy to use and get used to. The most annoying part as I recall were the online whiteboards which could crash or behave strange, not have enough writing area or didn't allow saving the content. For a short while a good alternative was google docs drawings, but it looks like they've removed the freehand drawing tool. So I'm still looking for something adequate there. Correction: Google docs drawings may be used as an online whiteboard and allows one to save the content. The scribble tool can be found under the shape button.
Edit: (in response to Willies comment). Stingy as I am I've only used free online whiteboards so I really can't complain. The best of these I've found were twiddla, scriblink and skrbl. Some of them have paid plans which probably increase the user experience.
Concerning the pen tablet I have an older version of the Wacom Bamboo Pen with which I'm happy. The fancier ones use a screen as a writing surface. I imagine that makes it feel more like writing on paper, but I'm waiting for those to merge with computer tablets.
