I have a 10 gal. tank now that I have had set up for over 2 months now and I want to move to a 30 gal. With out setting the 30 gal up and waiting a week for things to get settled can I not just transfer the water from the 10 to the 30? And just transfer decor and fish once I add the new water to fill the remaining space and let it get to correct temp.

You can do that and it'll probably help to a certain extent. It'll help more if you're using the same filter on both tanks as well, especially if you keep the activated carbon (where the beneficial bacteria grows). I say that but of course keep in mind your average 10gal filter is not adequate to filter water at sufficient rate for a 30g aquarium.

I'd probably fill the 30g tank about 50% with clean and treated water. Go ahead and add a thermometer (again you will want a larger thermometer, anything less than 150watts isn't big enough for a 30g tank) and heat the water up to the level you want it at, keeping the water temp in the new tank as close to that in the old tank as possible. Then start adding water from the 10g tank. Start the filter(s) as soon as the water level is high enough. In fact I'd actually go ahead and start using the filter for the 30g tank on the 10g tank immediately, so it can start building up beneficial bactera as quickly as possible. It'll get some out of the water it filters before you put it on the new tank. Anyway add the 10g tank fish to the 30g tank after you get most of the water moved over.

Don't add new fish for at least a month, because you need to be sure the nitrogen cycle is stable before adding any new fish. 15-25% water changes weekly will help as well.

Thanks. The only problem I dont think I even have any bacteria growing yet in the 10 gal. I've had high ammonia for 2 weeks now and everything I've done hasnt help so I didnt think I had any bacteria b/c it would fight off the ammonia. I've been to petsmart and asked them but they couldnt tell me anything different than I already knew. I feel like I have the knowledge in this but the ammonia they are just telling me to wait it out. I havent had any fish lost, but I'm afraid that will happen if I dont get this under control. So thats why I'm moving to a bigger tank I know a big tank is a little easier to keep under control. Any advise on the ammonia? I've been putting a stablizer in to keep from being harmful and I've done a big 50% water change.

High ammonia is normal for about 3 weeks after you start the initial cycle. The whole cycle takes about a month.