I'm using ubuntu and windows 7 dualboot,and have xampp installed on both I want to have access to one localhost directory whether I'm using windows or ubuntu. both systems are installed on the same partition.
I would recommend having the "shared" HTDOCS folder on your Windows side as Ubuntu can read NTFS natively.
You will need to use FSTAB to mount your Windows partition when Ubuntu boots so that you can access the web files.
Once you have a regular mount point for the Windows partition you need to create a symbolic link in Ubuntu so that your web files are still accessible by Ubuntu Apache but it can still read from its default location.
I'm only using the above code as an example. Please do further reading to get your scenario correct.