OK SwimLittleFish - if you really want to lose weight then then best ways are - swimming, running, cycling or fast walking. All respect to previous posters but raising your legs whilst on a laptop or playing on the Wii will NOT work! Otherwise Olympic athletes would do it!
You may burn one or two extra calories but you need to burn fat and tone up. And you can - you just need to sweat!
A half hour fast walk everyday will work wonders but you have to be slightly out of breath and 'glowing'! Lengthen your stride and kick up those autumn leaves and enjoy it. Go out specifically to walk - walking to the supermarket and then walking round the aisle does not count!
Swimming - I assume you can swim from your name! Again, half an hour of lengths. Try not to stop too long in between. If you're a bit self conscious is there a women only time you can go? Also I'm happy with my weight but prefer a tankini - Google it - as it covers up a bit more and you can get away with a less than immaculate bikini line.
Running - if you've never run before try Googling a running club near you. Lots are happy to encourage beginners. Running is the best way to lose weight fast but do invest in a good pair of trainers.
Cycling - do it at the gym if you prefer, try and keep the same pace for half an hour. This is non-impact like swimming.
Best thing to do is do a mixture of all of these - called cross-training - so you don't overstress any muscles. Try and do one of these a day (walking is the least strenuous) and the weight will drop off.
Sorry for the essay but losing weight is easy (really!) but you do have to exercise and SWEAT! None of this 'do some gardening' or 'play on the Wii' bollocks that you see on some adverts. Good luck.