I know the SGS3 has access to the 800MHz spectrum once it goes live. The EVO LTE probably does too.
There are about 30 phones on Sprint that support the 800 mhz frequency (that has already gone live in some markets.. such as Chicago.) You can see the list of phones that support 800mhz here: Frequently Asked Questions - Sprint 4G Rollout Updates
Basically everything released in the last 2 years supports 800 mhz. However, This is only CDMA/1X that these devices support. So, basically, voice, text and 1x data.
Sprint will roll out LTE on 800 mhz (using the freed up iDEN) spectrum next summer. None of the current phones support 800mhz LTE. Sprint is expected to release devices that support LTE on both 1900 and 800mhz Q2 next year.