I wrote this little script to make querying heasarc a bit easier its very rough but it's been useful for me.
It requires heasarc's batch command-line tool - as the does all the real work - (download,help), I called the alias xain (but it can easily be changed in the script)
I also use Matt Davis's jdutil class (which can be found here here).
Sorting of outputs is not setup for table specific columns, as I didn't need it.
If those things haven't put you off here it is.