Apparently, table salt is not a good idea. though, I've heard you can use kosher salt, or sea salt in replacement of aquarium salt.
If you slowly turn up the heat to about 84 or so degrees (someone correct me if I'm wrong) , and keep it that way until 3 days after the ich disappears, that'll kill the ich. At a certain temperature, ich stops reproducing.
You want kosher salt--a kind of salt that has not been iodized or contain any form of potassium. The two posts above mine offer good advice. The best medicine for ich is high temperatures, a bit of salt, and CLEAN CLEAN CLEAN water.
If the ich won't go away despite everything you do, I suggest a malachite green treatment.
Yep, raise the temp and use aquarium salt. Just know that you'll still need to continue treatment after the white specks fall off. They just go to the bottom of the tank, so they'll still be there. It'll take 1-2 weeks to be completely safe.
hmmm, well, if you live in an area where this is possible, you could stick your betta's tank (if it's relatively small) outside somewhere where there is shade all day, and take it inside in the night. So long as you have a thermometer inside the tank to moniter the water temps, you should be fine :)
The treatment I like to do in mild cases of ich, is the two cup method and move the fish each day from cup to cup cleaning and adding fresh water with each move for at least 3 days from the last day you seen the parasite on the fish.
In server cases I use the increased temp and aquarium salt 1tsp/gal up to 3tsp/gal along with daily water changes and deep substrate vacuuming for 3 days past the last day parasite was seen on the fish.
In the home tank, deep gravel vacuuming to manually remove the parasite and then provide the fish with a stress free stable environment to insure that re-infestation doesn't occur.