24p is 24 progressive frames per second. Kind of like 24 pictures showing up a second. This is the rate film cameras record at.
60i is 60 interlaced frames per second, interlaced footage has 2 fields (its kinda hard to explain, but its like seeing 2 frames at once i guess), after you edit, you should deinterlace it if your just viewing it on a computer, but TV's deinterlace the footage automatically. When you deinterlace the footage you see 29.97 progressive frames per second (i think)
My camera has a 24p, 30p and 60i option, i just record at 30p. 24p is kinda hard to film scootering because fast motions make the picture strobe, and you have to set your shutter to double the frame rate, so i would record with my shutter on 1/48, than you have to use lower apertures and the ND filters, its a hassle.