From: "Eric Lease Morgan" <[log in to unmask]>
>   1. What MARC field/subfield might I put this string?
>   2. How would I go about getting the string indexed?
>   3. How might I go about querying the server for records with this 
> string?

I can at least talk about the third question.  There was work on a marc 
attribute set, though not completed.  If you look at the oid register at 
http://www.loc.gov/z3950/agency/defns/oids.html you'll see that the latest 
work on it (second draft) was in 2000, 
http://www.nlc-bnc.ca/iso/z3950/MARC_attribute_set_2.doc. So if someone 
actually wanted to put it to use it would have to be completed.

For SRU there is a complete marc context set, 
http://www.loc.gov/standards/sru/resources/marc-context-set.html.

--Ray