Item description:

DISCLAIMER: This tool is not made by me! Give codemonkey85 credit, if you want to leave a thank's for his work, then go to the forum thread: [ Register or Signin to view external links. ]

From codemonkey85's post:

"Good news for the pokehacking community! Codemonkey85 from [ Register or Signin to view external links. ] has just released a tool that can modify Pokemon files in a very simple way.


The image is self-explanatory. Those are the editable values available at the moment.

Additionally, the program is able to decrypt and encrypt back PKX files. Files with the extension .bin are assumed as encrypted, and .pkx files are assumed as decrypted.

How to "trade" Pokemon between a 3DS and a PC
For those wondering, I got an explanation about this:
*Use a WLAN-dongle like a USB Wireless Adapter to create a Software Access Point.
*Use a program to analyse the network traffic in hexadecimal format while doing a Wondertrade. Wireshark and HexInject may work well for this.
*Find the encrypted Pokemon data inside the packets. It begins with 4 bytes followed by 2 bytes equal to zero, the full data must be 232 bytes.

(Thanks Zaneris for the hex data)
The first regular 4 bytes are underlined in green and the pair of bytes equal to zero are underlined in orange. Note that generally there won't be another pair of bytes equal to zero close to the beginning within the Pokemon data.
The header is inside the blue rectangle so the encrypted Pokemon is at offset 0x0068 and ends at 0x014E. If you didn't capture the header, the Pokemon will be at offset 0x003D and will end at 0x0124.

*After editing and re-encrypting the Pokemon by saving it as a .bin file, the received packets must be altered to include the new Pokemon. Having the received packets of the last Wondertrade, search for the encrypted Pokemon the same way as before and replace the HEX data.
*Inject the packets in another Wondertrade."

I had to upload the images to tinypic, they wouldn't work for some reason otherwise.