I was about four and a half months pregnant when I first felt it. I remember it being the creepiest, most beautiful thing that happened to my body. Hubby couldn't take the smile off his face when I let him feel it too (he was kicked in the face though as he was about to kiss my tummy).
Fetal movement, also called "quickening", can be noticed around the fourth or fifth month (may depend on a woman's built). Movements start from gentle tippy-taps, then progress to painful jolts.
When my baby turned seven months in my womb, she started doing twists and turns and combos of jabs and kicks! I also remember her doing punches when I lie down to one side that she didn't like. Her punch would command me to rollover. Okay maybe she didn't really "punch" or "kick" (or "headbang" to music), if you're a fellow mum, you know what I mean.
It hurt. But hey, nothing a pregnant woman's body cannot handle.
Fetal movement during the last month will slow down, for the baby's temporary abode will already be cramped by then. Photo above was taken two days before I gave birth. Luna didn't seem to care about her small space, she still stretched her limbs as she pleased!
How fast she grew... Now she's five months old, kicking me for real. And what great power her legs have!
Note: Fetal activity/movement should be closely monitored in the third trimester. Consult your OB-Gyn if you feel less than 10 kicks in about 2 hours.