boot or splash? boot is first screen. spash is 2nd.
change the file called welcome.96.png <-- spash ( i used resco file editor, other will work)
"2 ways to do it, there may be more, but you can flash No2Chems Rom from PPC Kitchen which allows you to use custom screens. or you can change welcome.96.png with total commander. If you Flash 5055-5067 you will need 3.35 radio, which I see you dont have unless you've upgraded since you made your sig. You can get the new alltel rom straight off of the HTC site. or you can flash the newer Spring Rom with the 3.39 radio, you will also need Olipro 2.x "
here;
http://forum.xda-developers.com/show....php?p=2233982