smbfs seems to have trouble with the access permissions on samba drives.
the numerical userid and the groupid are exported from the samba server. while this is a nice feature, it's practically useless because they are of course different on the client machine. specifying them with "smbmount //server/share mountpoint -o uid=user,gid=group does not have the desired effect.
so I hacked into the file /usr/src/linux/fs/smbfs/inode.c and changed the following. this results in all the files belonging to root but with read/write permissions for all.

hope I could help

/usr/src/linux/fs/smbfs/inode.c:
...
smb_set_inode_attr(struct inode *inode, struct smb_fattr *fattr)
...
// START Hack by exeon
inode->i_mode = fattr->f_mode | 0666;
inode->i_nlink = fattr->f_nlink;
inode->i_uid = 0;
inode->i_gid = 0;
// END hack by exeon
...