In Avid Xpress Pro HD there is a bin of conversions from Michael at 24p.com. If you take your 30i captured footage, drop it in a 30i timeline, apply the presets Michael has made, export, reimport into a 24p project, drop it in the timeline. Basically this utilizes the FluidMotion engine. In Xpress Pro HD, the FluidMotion editor is not available, but you can still make use of it. Michael has created presets on a Media Composer in the form of a bin, since Xpress Pro HD can import bins from Composer, and since the FluidMotion engine is still present, you can use the presets he has made. (and he has a lot for every situation)

Basically, using FluidMotion Engine, the 30i is sped up to 125% and then deinterlaced, when you drop it back down into a 24p project/timeline, it conforms to that speed. Audio still maintains sync.