If you look on youtube, there are GREAT videos.
But simply, shred paper into strips, soak in warm or hot water, tear into tiny pieces... You can let dry or send it through the dryer (even the washer) in a pillow sack, but if you use the washer rather than a bucket you will need to drain the pillow case A LOT.
You'll want to pound on it... so a meat hammer, sludge hammer, a shoe, your foot, your fist whatever your preference

You can use newspaper, flyers, computer paper, etc just make sure that it is non-toxic ink (most use...veggie oil base I think?) Trust me.... I pay 30.00 for my guineas, and that is food, hay, toys, and extras... I don't want it to be 130-200 for bedding! It's ridiculous LOL.
http://www.youtube.com/watch?v=WzaHFdwxzjk&feature=fvst
http://www.youtube.com/watch?v=MODxfJqD7M4
http://www.youtube.com/watch?v=VU0Vf_nPH-o
http://www.youtube.com/watch?v=nUqyFK04sto
Just a few :) most are pretty much the same. I am going to make some tomorrow if I can. If you get tons of flyers and papers like I do, that is the BEST.Apparently you can also use food dye to make it colored... I probably won't.