Reading 4Mbit SPI flash memory
I've never used bus pirate before, but how about trying to read the status byte first (it should be simpler and easy to confirm)? Maybe something like: [0x05 r]

Also, maybe your above command should be: 

[0x03 0x0 0x0 0x0 r]


Memory appears to be addressed as A23-A0. Where A23-A19 =0, A18-A16 specify the block that you want to address (Table 1), then you specify the specific address using A15-A0 (4 KB of space). To Read Address 0x030000: 

[0x03 0x3 0x0 0x0 r]


Good luck,

-Chris