Hey, I´m running openSolaris LiveCD on a computer that runs Windows XP.
How can I mount the 2 partitions I have in Windows, and be able to access them from the Solaris?
If your XP partitions are FAT based, you can directly mount them as pcfs is natively supported by the OS. Use something like "mount -F pcfs /dev/dsk/c0t0d0p1 /mnt" assuming you want to mount the first partiton of your the disck connected to controller 0 (you need to first figure out what your disk device is).
If your partition is NTFS based, there are already packaged solutions like ASntfs-3g-2009.4.4 on sunfreepacks.com. However, I doubt they would be installable on a live distribution which is definitely read-only.
If it's a live CD then each time you can install FSWfsmisc package from the net and then mount with "-F ntfs". Details here.