print_r(unpack("H*","The quick fox jumped over the lazy brown dog"))
Array ( [1] => 54686520717569636b20666f78206a756d706564206f76657220746865206c617a792062726f776e20646f67 )
T = 0x54, h = 0x68, ...
You can split the result into two-hex-character chunks if necessary.