That's odd, most PSUs that I've used orient the labels to work with fan down. Fan down is the preferred way if you have the grill on the bottom so it sucks in clean air from outside the case. Otherwise fan up if you don't have such a grill.
San Francisco: Gigabyte GA-Z77X-D3H | Intel i5-3570k @ 4.5ghz | 16 GB DDR3 @ 1866 | Gigabyte WF3 7950 @ 1125/1500
Honolulu: Gigabyte MA790X-UD4P | AMD Phenom II X4 955 @ 3.8ghz | 8GB DDR2 800 | Sapphire HD4890
London: ASRock 4CoreDual-VSTA | Intel Dual Core E7400 @ 3.1ghz | 2GB DDR2 667 | ATi X850 XT @ 540/590