WinZip is the standard for compressing files and combining multiple files into one file. It is used by millions of people to create and open zip files and is very easy to use.
One of the nice features of WinZip is its ability to split your zip file into smaller files. So you have your 900 MB Zip file and it won't fit on your 700 MB CD. You can have WinZip split the file into two separate zip files that you can burn on to two CDs and then combine back into one zip file later on. This can also come in handy when emailing large zip files that are too big and go over your email attachment size limit.
To do this all you need to do is open your zip file with WinZip and then go to Actions and then Split. From here you can name your zip file and tell it what size you want to break it down to. You can select one of the pre set sizes or choose your own custom size. The size will determine how many zip files you will be creating out of your original zip file. Choose a size that's small enough to satisfy your requirements but not too small that you have more zip files than you need.
You can then choose where to have the zip files created and then they will be there after the process is complete.