Excellent idea.the beauty is that you can plant them in the ground and the paper will rot.
I have added it on to my project of saving all those brown toilet paper cores and bundling them up with wire, filled with soil and placed on an old water heater tray bottom. My neighbor laughs every time she walks by.
I do the TP pots too. They are great for larger seed like squash. I write on the side of the roll with a magic marker. Fill it with soil (slightly packed in) leaving about a half inch lip on the top end.. Stand it up in a cat litter tray and plant a seed in each tube. When it's ready to plant I use a bulb planter to make the hole and drop in the tube. No transplant shock. It's free and the lip of the tube protects against cutworms.... I love it!
I've used both newspaper and tp pots, and just a note: make sure to either leave the bottom open (sitting them in a tray until the roots are good and strong) or remove or unfold the bottom before planting, and in some cases I even slice the side. They do break down in the soil, but generally not fast enough to get out of the way of the roots that grow. Also, make sure to plant ALL of the paper. If any of it sticks above the surface of the soil, it is wicking moisture away from the roots.
They do get rather soggy and some do fall apart. But certainly no more so than soil blocking, and I love(d) my soil blocker!
http://www.johnnyseeds.com/c-455-soil-block-makers.aspx I had the 4-block sort. I made the mistake of loaning it out last year. I have done my seed starting without it this year and I miss it! I might just buy a new one, or try some of the diy versions I've seen online.
They need a rather specific sort of mixture to work well, but once you've got your "recipe" down, it's awesome how my seedlings come though with no pot at all.