Put the new kitten in a room and don't let him out for a while - after a little while, once the kitten's gotten used to being there, you can also let him into various other rooms when the older cat is OUTSIDE - this allows both the kitten and, more importantly, the older cat to get used to having each others scents around, and means that they are aware that there is another cat around.
After some time, and you feel that the older cat has gotten used to the kitten's scent, you can start introducing them. I suggest having them in the same area at feeding time - making sure to keep an eye on them so niether tries to steal the other's food - before putting the kitten away again. This means they can get used to each other's presence while distracted by food.
Once the cats don't seem to mind each other when eating, you can consider having the kitten 'visit' the older cat, by bringing him out. If the older cat hisses at the kitten, take the kitten back immedietly, and continue to only introduce them at mealtimes for a little bit longer.
You may have found that, somewhere in these past few stages, your older cat has started urinating everywhere. This is a combination of marking their territory from the new threat, and simply expressing their anxiety. Give them love, patience, and keep going at their pace. Your cat will get used to the 'intruder' and stop doing this.
After a little while, the older cat will not worry about the kitten so much, so long as it respects his space. You will probably feel safe about leaving them alone in the house about now, but its best to be on the look out for negative behaviour for a little while longer. If the older cat hisses, simply put the kitten into another room and let him play there.
Don't expect them to snuggle up to each other when they're sleeping, or be the best of friends or anything like that, however. Your older cat's gotten used to being your one-and-only, and its very difficult to keep up with a kitten at his age. Add this into the fact that different cats have different levels of being social, and you'll find that how close they become is up to them and time. You'll probably notice that they get on better and better over the months, just let them go at their own pace from thereon in.
Throughout the whole process of introducing the kitten, I cannot stress enough how important it is to give your older cat as much love and time as he's being used to. There's nothing wrong with having the kitten scent on your hands - it'll help him get used to the scent - but you have to resist the urge to spend all your time with your kitten; the last thing you want is for your older cat to feel replaced, from which jealously stems.