I feel like there might be a more efficient way to do this but here's my naive solution:

function bytesToAddress (bytes b) constant returns (address) {
    uint result = 0;
    for (uint i = 0; i < b.length; i++) {
        uint c = uint(b[i]);
        if (c >= 48 && c <= 57) {
            result = result * 16 + (c - 48);
        }
        if(c >= 65 && c<= 90) {
            result = result * 16 + (c - 55);
        }
        if(c >= 97 && c<= 122) {
            result = result * 16 + (c - 87);
        }
    }
    return address(result);
}

This seems to be the go to code around here:

function bytes32ToString(bytes32 x) public returns (string) {
    bytes memory bytesString = new bytes(32);
    uint charCount = 0;
    for (uint j = 0; j < 32; j++) {
        byte char = byte(bytes32(uint(x) * 2 ** (8 * j)));
        if (char != 0) {
            bytesString[charCount] = char;
            charCount++;
        }
    }
    bytes memory bytesStringTrimmed = new bytes(charCount);
    for (j = 0; j < charCount; j++) {
        bytesStringTrimmed[j] = bytesString[j];
    }
    return string(bytesStringTrimmed);
}

I'm sure you can change out those 32's to get the length needed. But hope it helps!