You can get AutoHotkey from
www.autohotkey.com for free.
Use this script with AHK to ease bunny hopping:
CODE
*Space::
Loop
{
GetKeyState, state, Space, P
if State = U; The button has been released, so stop the loop.
break
; Otherwise:
Send, {Space}
Sleep, 1; i.e. 30 ms delay between clicks. Adjust this value as needed.
}
return
You can change "Space" to whatever you want to hold down to jump. The names of the buttons are in AHK Help file under "Key List (Keyboard, Mouse, Joystick)" The third "Space" must be set to what you have binded jumping to in Half-Life 2.