Cold shower, turn the A/C on for a bit, sleep with a fan on you, drink an ice cold glass of water. Those are some of the things I've done/am doing. DH hates that we're now in November in New England and I still have the A/C going at times. )
Won't help while you're sleeping obviously, but if you get overheated during the day, try running ice cold water over the inside of your wrists. This cools me down quickly. Of course, dress lighter, drink cold water, etc. as well.
At night I have found that I should just go to bed naked, otherwise I end up waking up in the middle of the night sweating and overheating and taking my clothes off anyway.
I take off most of my clothes when I walk through the door. And I sleep in a tank and undies. I always run cold but as soon as I get pregnant I'm a furnace!
I have slept with ice packs during this pregnancy... Also, I second pp, get a fan. It's in the 30s here at night now and I've got windows open and a fan blowing on me, sleeping in barely anything and just a light sheet. Most nights, it works. If it doesn't, I drink ice water and stand in the freezer for a minute, or try cold shower.
Sleep in as little clothing as you feel comfortable (naked is best) and regulate with different weights of blankets and sheets. That way you don't have to take off clothing which wakes you up even more and can throw off the comforter or whatever. I'm so hot at night that I just cuddle the blanket and barely have it cover it me at all. I haven't had to break out the fan yet, but we've been keeping the heat set to 64F (with DH and DD wearing fuzzy pjs and piled in blankets and me with nothing and still hot, ugh).
Re: any good remedies for feeling over heated?