I`ve never tried it with a laptop before but it should work in the same way as taking a tv and receiver to your dish
You would need something like this _http://www.google.co.uk/products/catalog?q=usb+dvb-s2&hl=en&safe=off&prmd=imvns&bav=on.2,or.r_gc.r_pw.r_qf.,cf.osb&biw=1280&bih=852&um=1&ie=UTF-8&tbm=shop&cid=4159614292557251944&sa=X&ei=3xhfT6b6BIL78QOr8vCjBw&ved=0CK4BEPMCMAY
You would plug it into the laptop via USB and into the LNB via coax and run the software provided, then you tune the software to a free to air channel on the satellite you want to align the dish to
Then all you will have to do is watch the laptop screen for signal/quality and a picture as you are aligning, when you get a picture and the signal/quality is good and you can confirm it is on the satellite you want, you can then find a weeker transponder and tweek the alignment some more till perfect
I think there is also 3rd party software for PC DVB-S cards /USB DVB-S dongles that turns your PC/laptop into a sat finder but someone else will have to comment on that