[shadow-tech]

Ext_rom info:
Alltel_ShopNow.cab ---------------------- Alltel Shop Program (purchase appz and games over the phone)
Alltel-Nav-htc-6800mr-2.0.08.cab -------- Alltel Navigation Program (30 days free then charge monthly fee)
Cab_Alltel_Magmic_dll.cab --------------- Allltel Games and More Program (loads PIE page. says 'no games availible for your device')
express_240x320_props.arm.cab --------- Express Program (I think its like news, weather, mail, stocks)
getmail.ppcwm5.Release.alltel.cab -------- Get mail (havent used this yet)
Hidden.cab ------------------------------ Alltel themes (kinda cool ones, green is actually gold)
HTC_Alltel Handango.cab ----------------- Handango
signed_080808_7500_Alltel_2.02.sa.cab --- PPST setup stuff
WMP.cab -------------------------------- SDP support for Windows Media Player (Session Description Protocol)

let me know if you know what all some of the other ones do.

I would say only these to should be used:
signed_080808_7500_Alltel_2.02.sa.cab
WMP.cab

the rest is junk.