Get ear plugs. As long as you love a talky cat they're fantastic.
Haha this. I actually do sleep with ear plugs. Apollo is a constant talker.
I have two siamese mixes and they're very very active cats. They have a lot of energy and are very social. Make sure you have a good scratching post for your kitten, preferably something (s)he can climb (you could start with a small nest/post for a kitten and get something bigger when (s)he gets older).
Siamese love to play, as do kittens in general, so you'll want to pick up some toys, although the right ones may depend on your individual cat. My cats enjoy ping pong balls, crinkle balls, and other small toys they can bat around. A sturdy toy like a big soft catnip mouse might be a good idea, as sometimes they play a little rough. This thing has also been a big hit with my cats: Star Chaser Turbo Scratcher Cat Toy at PETCO
It's nice because it gives them something they can play with easily when you're not around (if you have to go to work, school, etc.).
Also be prepared to devote a decent amount of time to interactive play as well. A feather wand or something else they can chase is good for this.
Siamese are definitely not usually mellow or anti-social cats. They are very "in your face" and your new kitten will probably want lots of attention. And like Dave said, may yowl a lot to let you know.
And lastly, be prepared to have lots of patience! Kittens get into everything, and siamese cats , being very energetic and curious, do this doubly so. It's been a slow process teaching my cats what is okay and what is not okay. If Apollo is any indication of the usual personality of the breed, they can be a little stubborn, and you may have to go through lessons multiple times. Usually any persistent bad behavior on the part of my cats means they're getting bored, so I take that as a cue to give them some extra play and attention to help them burn off all that energy they have pent up.
Oh, and try to get your kitten used to having nail trimmings done at an early age! Because siamese are so playful (and usually will want you
to be somehow involved in their play) you may frequently find your hand in a prickly kitty beartrap, and when this happens, it's much better when they have trimmed nails.