Typically any handset which is 850Mhz (3G, WCDMA) compatible will work with Boost.
You need to ensure if your device is from another carrier other than Telstra that the device is unlocked.
To check if your device is compatible on the Boost (Telstra) network click here, you will need to enter the IMEI (Serial) number of your device which can be obtained by entering *#06# into your keypad on your device.
Before purchasing or attempting to use a phone purchased from another country, you must ensure your device is compatible with the Boost Mobile network, CDMA phones commonly found throughout the USA will not work!
Please let me know how you go with this process and if you require any additional assistance.
I hope this helps you out
Another option that worked for me was fronting to a Telstra Store and requesting a Blank SIM from them. They will give you a Blank SIM card FREE of charge and then all you need to do is call 125 8881 and ask for a SIM Swap process. The Blank SIM I requested from Boost Customer Care took around two months to receive, so don't hold your breath.
Let me know if you have any issues with this process