If the disk is partitioned, you should see some further messages in the log. Look for something like this:
GEOM: new disk da0
 f:80 type:165 s(CHS): 0/1/1 e(CHS):521/224/63 s:63 l:8385867
GEOM: Configure da0s1, start 32256, length 42393563904 end 42935391659
GEOM: Configure d0s1b, start 0 length 536870912 end 536870911
And so forth.
At any rate, you can also check out /dev. You should see entries like this
What you will eventually want to mount is /dev/da0s1e, or whichever partition actually has your data on it. Then, you also need to know what the filesystem is on the partition. Assuming it is FAT (or FAT32), you could then mount as follows:
mount -t msdosfs /dev/da0s1e /<some directory>
Where <some directory> is an empty directory. On possiblity, do the following:
mount -t msdosfs /dev/da0s1e /winxp
If the filesystem is NTFS, then I think you want to substitue as follows:
mount -t ntfs /dev/da0s1e /winxp
But I'm not 100% sure that NTFS is supported fully.