The best you can hope for AFAIK is laptop screen / external monitor dualview. My Dell Latitude D600 supports this.
However, there is another solution. You could get a USB 2.0 to SVGA adapter. This will add a 2nd display devices via USB for an extended desktop. Its about $90. I havent used it before but
HardwareCentral.com has a review of it and you can buy it from
CyberGuys.
I use dual monitors at home and at work for programming and such. I would also highly recommend purchasing
UltraMon. This is a kick ass multimonitor utility, especially usefull if you are mixing 2 different graphics cards.