I use http://remush.be/esperanto/alunikodo.html when I'm not using my own computer. Just replace the text in the window and push the green button corresponding to the system you used, f.i. cx gx hx jx sx vx → ĉĝĥĵŝŭ On my computer I installed UBUNTU, which allow me to type ĉĝĥĵŝŭ directly.