Recommend a USB programmer

Riva:

CrossRoads:
Atmel AVR ISP MKii,
Can do bootloaders, sketches without bootloader, all the ARV devices.

Does this mean the USBtiny & USBasp cannot directly program memory or burn bootloaders?

Yes they can. However the USBtiny for sure can't write to the larger flash memory addresses that the mega boards use, but works fine for the other chips having flash of 64kB or less.

Lefty