I've made port a couple ways, both of them are more hands on than regular wine.
1) easiest: start a high gravity wine, somewhere in the 1.2-1.3 range, with a powerful yeast. EC1118 is a common one, as is K1V-1116; they are pretty neutral as well which can be good. Some of the Burgundy yeast strains are great as well and can tolerate a lot but impart some nice signature flavors. When the wine is at about 10-12% ABV, or is as sweet as you want it (typically 1.03 range), add crushed campden, a bottle of O.K. brandy (no need to go top shelf), and (if possible) cold crash it.
2) slightly more hands on: again start with a high gravity wine, and continue to add fermentables (I like grape concentrate mixed with sugar) as the points drop, along with a little yeast nutrient. Eventually the yeast will poop out; but try to time it where they kill out on the low side (1.01-2ish). you can always backsweeten.
It is good stuff, but takes longer to age out. My cherry port is just now ready to bottle and I started it in August 2012. It was just too boozy and sugary before, now it has a nice, deep, warm silky sweetness to it that is fantastic with chocolate, a nice young lady, and a long winter night.