By design, Mac OS X only shares a user's Public folder. Limited file sharing is a feature of Mac OS X, which enhances security.
There is a workaround, which is less secure:
You can share files from any folder on any volume by logging in at the client computer as an Admin user. Admin users log in like any other file sharing user, from either the Chooser or the Connect to Server dialog of the client computer. The Admin user for a computer is either the first user created after setting up Mac OS X or any other user designated "Admin" in the Users pane of System Preferences. A computer can have more than one Admin user.
1. A user logged in as an Admin has complete read-write access to all files on all volumes connected to a computer running Mac OS X. The level of access that an Admin user has when logged in with AppleShare is greater than the same user would have when logged into the Mac OS X computer directly (barring use of the Terminal). You should never allow other users to log in remotely as Admin in an environment in which security or user skill level concerns could result in the unauthorized introduction or deletion of data. For users familiar with UNIX-style operating systems, the Admin user is similar to a root user.
2. Do not connect to your Home directory and the disk that contains it at the same time. If you have connected to one, drag it to the Trash before connecting to the other. Failing to take this precaution presents a situation in which you could attempt to replace a file with itself, resulting in the loss of the file.
Note: Two volumes with the same name may not appear in the Chooser or Connect to Server dialog. This occurs, for example, if you have both Mac OS X 10.0 and Mac OS X 10.1 installed on different disks or partitions on the same computer. Since both disks are named "Mac OS X," only the startup disk is available.