I have been using Jason Emricks free (GitHub) Send to InstaPaper app on my BlackBerry for awhile to bookmark pages I need to visit from my desktop. We have been lacking a client to read InstaPaper items on your BlackBerry until InstaRead came out. InstaRead is sadly not free but is available for $1.99 on sale from $3.99 in the store.
InstaRead simply lets you view your bookmarked articles from your BlackBerry that you have stored in InstaPaper. It will save and sync the read process so your workflow is not lost. The only complaint I really have is the interface looks like BlackBerry apps from 4 years ago.