Some old flashes will work, but not all
See here http://www.mhohner.de/sony-minolta/flashes.php
and check the column that says "Digital Ready".
Please not that the flashes should work, you just won't have TTL and would have to work on full manual. Full manual is cool in a controlled setting, like a studio or small get together, but can be a handful in situations where you are constantly moving (changing flash to subject distance) and the ambient light keeps changing (assuming you wanted to match the ambient).
If you do plan on getting a newer flash, I'd probably skip the 36 since it is fully automatic and doesn't have manual controls, and if possible, test the flash on the camera body before you buy since some Sony flashes have an issue with the shoe mount being wobbly.