Ahhh! Wrote a long post but lost it. So, the short version - yes, you can do it! We just did, a week and a half ago. DS turned 3 in Feb and was ready. But wouldn't do it himself. I decided *I* was ready and told him the next day he'd wear underwear. He went through about 7 pairs of underwear/pants combos that day (would start in his underwear, then run to the potty), but was learning and the next day did much better! Third day I think he was dry!
It wasn't "painless" for him though - for a couple days he agonized over the decision to use the potty each time, knowing he HAD to (or have wet underwear) but he paced around like a woman in labor, lettign out yells or whining "noooooo!" while he held it in. I felt bad... but I knew deep down he was ready and could do it. He was just nervous? or scared? or sad about the new way? I don't know. But he was proud every time he finally did it, and after a couple days he was great, and asked to wear underwear at night, and he's dry at night too!
Things we did that I think were helpful: We had a chart (got it off a pullups box actually) and cute stickers and cookies for celebrating (we used that word - celebrate! Not "reward".... I didn't want it to be taken that way). The cookies were supposed to be for filling a row on the chart - but ended up being promised for the first time he did use the potty, and other victories! Shameless, but I felt it was useful and necessary.
One other thing was that he was resisting the potty but liked my suggestion of standing to pee in the bathtub. It got him over the mental block about the potty I think. (He used the potty for poop every time though.)
Good luck! You CAN do it!