Reading "multi-session" disk without Nero

I'm using a burner software called Sonic DigitalMedia LE. It has a feature called "appendable" by which, it says, "Files can be added or "appended" to a disc as often as you like until the disc is full." My impression is that the previously-burned files are not overwritten during the next burn, and thus are available for reading. I did three appendable burnings on a disk and the "disk information" feature of Sonic shows that there are three burnings on the disk. But, only the latest one shows when I open the disk with Win XP. I know that Nero has "multi-session" which allows reading of all burnings (sessions). I don't have Nero. Finally--my question: Is there free software out there that would allow me to read all the burnings on my Sonic appendable disks? Thanks.