What distribution are you using?
There are several options that must be correctly configured in the kernel for the bootsplash to work properly-- in fact, iirc, the kernel must be patched to use the bootsplash in the first place. I think that the patch may have been integrated at some point, but sorry to say I don't know at what point, if it has in fact occurred. But you may very well have no need for any application files from bootsplash.org-- the applications needed may be included with your distribution (whatever it may be), and any kernel patch is probably included in the distribution's custom kernel.
After the kernel is correctly configured, then the bootsplash application itself must be correctly configured, and following that, the bootloader must be configured to display it.
I have used the bootsplash on several kernels, ranging from 2.6.3 to my current 2.6.7, and I can confirm that it does work on all of them, so the problem is more likely a configuration one than anything else.
If the box is a public display box, why not just boot before the "public" shows up? That way, they won't see anything to be scared of. It's not like a Linux box needs to be rebooted all that often.