sudo mount /dev/sda1 /mnt/usbflash -o users,umask=000
or if already mounted: sudo mount /dev/sda1 /mnt/usbflash -o remount,rw,users,umask=000

Add the following line to /etc/fstab
/dev/sda1 /mnt/usbflash vfat noauto,users,exec,noatime,umask=000 0 0

btw, this forum section is for posting tips and/or tricks, not asking questions.