Many groups cater to the operational and administrative interests of in-house lawyers and their departmental colleagues. This first cut at a compilation of those groups includes a dozen that exist or may exist (and several metaposts that I have linked). Please let me know of others.
Contracts. For example, the leader is probably the International Association of Corporate Contract Managers (See my post of Jan. 21, 2010: IACCM and empirical research on commonly negotiated terms.).
Diversity. Minority Corporate Counsel Association (See my post of June 17, 2008: diversity with 29 references.).
E-discovery. Anne Kershaw, an accomplished consultant, hosts a group and there is one in the Mid-West (See my post of July 26, 2008: e-discovery with 24 references.).
Environment and energy. One probably exists, if only as an informal information exchange or listserv (See my post of Jan. 20, 2010: speculation on an in-house group.).
Litigation. My friend Jeff Paquin has for years run the Council of Litigation Managers.
Operations managers. David Cambria at AON has nurtured a group, sometimes referred to as the Chicago Legal Information Council (CLIC) and there is the Corporate/Government Section of the Association of Legal Administrators (See my post of Feb. 13,2008: administrators with 21 references.).
Outside counsel management. Fred Paulmann, who has left Pfizer to consult, built up a group of in-house lawyers and others who care about management of outside counsel.
Pro bono. (See my post of Aug. 24, 2008: pro bono programs of law departments with 12 references.).
Procurement. I know of an ad-hoc group of legal procurement managers (See my post of March 1, 2008: procurement with 17 references.).
Project management. There are books written about the topic, such as one by Michael Bell and another by guest blogger Stephen Levy, but as yet no group that I know of (See my post of June 24, 2007: project management with 5 references; and Sept. 22, 2009: project management with 13 references and 1 metapost.).
Six Sigma. It would not surprise me that some group exists to facilitate communication among law department disciples of Six Sigma (See my post of Feb. 13, 2008: Six Sigma with 18 references.).
Technology. The leader is ILTA (See my post of Feb. 13, 2009: first of a series on survey data from the International Legal Technology Association regarding in-house technology.).