IMPORTANT NOTE: wifi error and solution!!
Be aware WIfi conexion won´t work with that method after rooting (at least 4 known cases and me).
I had to install .zip custom ROM for it to work, here it is: http://www.megaupload.com/?d=3RC9EE9Z
it's the only one until now for HTC explorer so has some limitations: only english and chinese languaje, has a few preinstalled apps in chinese, and no android market, install it yourself and don't forget to do a complete reboot of phone (untick fast reboot option) to prevent market from crashing when trying to download any app.
that you are free to modify preinstaled apps adding and deleting files inside the .zip (system/app/) and will be installed in the "rom memory" not internal one
be carefull not to delete important system apps but there are many widgets and stuff not needed
and yes, we need a BOX for HTC explorer!!
Htc Explorer (pico) "JaggyRom" HERE
HTC explorer root tutorial Here