C. - The shower thing is not a good idea, it will just scare your child more for showers/baths and sends a BAD Message.
My son - almost 4, wasn't even interested in potty training until he was 3 1/2. It took us a solid week to get him into the habit and everything worked. What I did when he had an accident (when all the other stuff the 'books' said didn't work (show disappointment, tell him your sad, don't yell, etc) My son is BIG into DVD's and tv shows. He also loves to play on the computer. We started with when he went in his pants and had an accident, we turned the TV off until he went into the potty again. This worked wonders. Find something he REALLY REALLY likes (a special toy he plays with every day, etc) and take that away until he can use the potty again.
One thing that didn't worked for us was taking him to the bathroom to use his potty chair, that didn't work because he had trouble knowing that he had to go and he didn't want to take time away from playing / watch tv. We put the chair in the same room as he was and that worked, then we moved into the bathroom. The first few days was terrible, it felt like a MONTH, but in reality, he was 100% going on the potty with very very very little accidents on the 7th day of training.
I know you're not supposed to 'punish' your child with toilet training, but taking away his shows was the only thing that worked for us. We did the sticker program thing which worked a little, and even gave a reward that when he got enough stickers, he got to do something special - for him it was going to Chuck E. Cheese. The sticker thing wore out fast and soon he didn't even care about putting a new sticker up when he went.
I'm happy to say that we started him off sitting to go potty and now, my husband showed him 2 days ago how to stand and that's how he's going now. He's very proud now to be going 'just like daddy'!
Good Luck and Hang in there. It is really true that all of a sudden, they just get it! It's wierd when it happens.
J.