Congrats A.,
I just had a baby three weeks ago and did strength training, spinning, and yoga until the day before I delivered. I borrowed some books from the library, read fit pregnancy magazine, and joined babyfit.com (free and has many articles and you can join a group from your due month that will help you stay motivated-this was by far my favorite resource). The only real difference that I noticed (and from talking with my doctors) is that if you are doing anything on your back such as strength training make sure you are on an incline. I did abdominal work on my back until about 7 months and then after that still did abdominal work but doing table top, pelvic tilts, etc (babyfit has good resources for this).
The only other thing I only did as much as I felt comfortable. Some days I felt really strong and other days I didn't and I just did as much as I could and didn't push myself. Surprisingly I did not really alter my workout that much. The hardest part for me was probably the first trimester.
Kind regards,
V.