Use two net connections simultaniously

Hi everybody,

I have two internet connections one through BSNL Broadband which I use for my desktop PC, and other a Tata Indicom plug2surf usb modem connection which I use for my laptop. Most of the time my Tata indicom modem sits idle as I use it only when I am traveling. I just want to know if there is a way I can use these both connections simultaneously for getting total speed of both connection for greater download speeds.