Editing the Splash Screen
Editing the Splash Screen is a fairly straight forward process, suitable for your first blender programing attempt.
Finding the appropriate files in the source files
This is the location of the current splash screen being used by blender. First you have to create your new splash screen. Do this by editing the current splash screen in your favorite image editing software ie Photoshop, Gimp even Microsoft's Paint program will do.
Once you have created your splash screen save it as splash.jpg If you're using a version of blender 2.5, the new datatoc.py supports .png files, so you should probably save it as a .png.
Find this file in the same location and compile it using any compiler you have. datatoc.c is a small program which converts the JPG image to text format suitable for blender to interpret. You do not need to do this if you are using Blender 2.5.
I compiled it with the following commmand
gcc -o datatoc datatoc.c
once compiled you will have a program called datatoc you then use this program to convert your splash.jpg to a splash.jpg.c file by typing the following at the command prompt. Do not do this with Blender 2.5
python datatoc.py splash.jpg
giving you a splash.jpg.c file
If you do use blender 2.5, than there is a python script (that supports .png files) that does this. Invoke it with:
giving you a splash.png.c file
If using a version of Blender prior to 2.5, copy your splash.jpg.c file to
replacing the original. If using Blender 2.5, copy your splash .png.c file to source/blender/editors/datafiles
Now compile blender as you would normally.
All done, you now have a new splash screen!