What you do is open one of the default title screens to find out the dimensions and colour pallete stuff in Photoshop or whatever program you wanna use.

From here you can create a new 'project' and simply create you title screen and save it as the same format as the default ones are.

Open RPG maker, import title screen and select you newly created one. From here, go to the database and go to system 1 or 2(same one as the battle music selection,etc.) and there is a thumbnail of a default title screen and a button you can click to select other ones, do so and select your title screen. You can also do this for a game over screen.

YAY for crappy explanations!

Hope it helps though. Someone else will prolly post the dimensions, etc. I can not remember them.

"why I've gotta be one of the cool kids just to walk by/
- without being tripped, thrown down on the ground and kicked/
Insulting me for no reason, I was treated like shit/
The teachers let it happen/
I've even seen some of them teachers laughing/
That's why I had a smile on my face when I started blastin/" - Ill Bill - The Anatomy of a School Shooting