I was in the same boat back in 1994.  I got the idea from seeing someone else do it.  I picked up on it and would screw around with it when I would go practice.  Walked into league one night and could not get a ball to hook for nothing with my one handed release.  So a friend of mine tells me to try the "two handed thing".  I shot 740 that night and never looked back. 

For me, I was already averaging almost 220 one handed so even though there was a bump in average, it wasnt a huge one.  I think I ended up that season right at 230.  The single biggest thing that switching to thr two handed style, did; was it allowed me to play deeper and still carry.  Back then, the balls were not that strong yet.  So even with my 300ish rev rate, when I had to get deeper, I did not have the pop on the backend to carry.  Now since my rev rate is low-mid 500s, I can carry from 5th arrow as good as 2nd-3rd arrows providing I have the right ball matchup.  It definitely makes the game more fun because you get to see pins fly around in a manner you are not accustomed to.  Make sure you go have your axis point remapped by a pro shop as I am sure your axis point is going to change from where it is as a one hander.

Also make sure you are mentally stronger before switching over simply because you are going to have the purists/traditionalists out there talk about how they think it should be illegal.  One last thing......make sure to check on the rules in regards to thumb holes and weight holes as there are a couple rules specifically for those that dont use thumb holes that were added to the rule book a few years ago.

When I was working at USBC, I volunteered to work with Bryan O'Keefe and Nick Bohanan of the coaching department to see what it would take to convert somone from one handed to two. I stuck with it for a couple of years, and it was eye opening. The biggest tips I'd give you are as follows:

1. Get your body prepared. I'm a somewhat muscular guy in the upper body, but I lack flexibility. The unique body positions of two-handed bowling depend on flexibility. Make sure you can handle it so that you don't injure yourself.

2. Experiment with new and different surfaces and drilling layouts. Don't think that you want everything shined up and drilled for length. On the contrary, some of my best reactions came from stuff that read the lane early and blended things out. I also found much greater use for urethane and plastic as strike balls on certain patterns. I bowled a PBA regional in Dallas and was tied for 5th place on my squad - until I fell apart the last two games - using a plastic ball on Chameleon. I simply had a look nobody else had. That's what two-handed does sometimes. In any case, keep an open mind and really learn your equipment!

3. Experiment with hand position changes. As a two-hander, you can literally rotate how the ball sits in your hands in your setup, and those changes can cause big-time changes in ball motion. I got the tip from Cassidy Schaub!

4. Be patient. Like learning anything, you'll have some days when you think you've got it mastered, and there may be others when you almost trip over yourself doing it. Just remember why you started doing it in the first place, which was to make things more fun and interesting.

5. Ignore anyone who wants to talk crap about two-handed bowling. It's a viable style. Hell, if you can do it well, you can damn near be unbeatable at times because you'll be able to achieve a reaction nobody else can. It's awesome when that happens, but it breeds even more contempt.

Best of luck. I've gone back to one-handed bowling, but I don't regret taking two-handed for a test spin. As others have said, it was a lot of fun. I'll never forget some of the ridiculous pin action I got while bowling that way. It was a head-turner. Good luck!