Hi,
Sorry I'm late replying; hope you are still checking.
I was on bedrest with both pregnancies, first at home and with my second born, in the hospital and away from my toddler. All the other ideas are great, but probably what she would most appreciate is any help you can give so she will follow her doctors instructions in order deliver a healthy baby! This would include driving her to her doctor appointments, running errands, and helping with things on her To Do List that she wanted to get done before the newborn arrives. I was frustrated that I didn't have access to a computer or the internet and had to wait for my husband or a nurse to look something up for me. You could help with that or help her find a notebook computer to borrow.
I'd recommend the bedrest support group website, sidelines.org to her, and you could help her line up a support person on there (or you could e-mail me and I will be happy to share my support too!)
Help her think of creative things she can do to pass the time other than reading, talking on the phone or watching TV. I organized my recipes while on bedrest, updated my address books, Christmas card lists, etc.
It is very frustrating to have so much time on your hands to think, and those thoughts often turn to worries about the baby. And she's probably constantly thinking of what she needs to do but can't (or shouldn't) get up to do.
The important thing is to give her confirmation that her time on bedrest is very important and very worthwhile for her unborn child, and for you to help her keep her spirits up and keep focus on a healthy baby. You are a very good friend to want to try to help her! Best wishes and again, feel free to contact me if she wants to vent to someone who's been through a similar experience.