Okay so I want the Katana® DLX by Sanyo® by Sprint but I want to use it with Boost Mobile [ i currently have Verizon right now] so I was wondering could I use it with Boost?

Boost Mobile uses iDEN subscriber identity modules (sim cards); nextel also uses iDEN sims. Some Nextel & southernlinc phones could possibly be unlocked to work with Boost, but since Verizon and Sprint use CDMA networking, a Boost iDEN sim wouldn't be compatible with a CDMA phone. There wouldn't even be any slot in which to insert the SIM card. You could use Boost mobile phones, unlocked Nextel or other iDEN phones (unlocked)---

you'd have to either get the Katana unlocked to use it with your Verizon, go with a new Sprint contract, or check out similar phones that are iDEN compatible...

interesting question !!