I think it's highly unlikely that Airbus will get into the fighter/bomber business in the near future - after all, current European designs (Eurofighter Typhoon and Dassault Rafale) are designed to last around 30 years!
Airbus, however, is already present in the mil market: they have a Multi-Role Tanker Transport programme going with the A310; it's being used by the Luftwaffe, the Ejercito del'Aire (Spanish Air Force) and the Canadian Air Command as a Cargo/Air Refuelling aircraft (with underwing FR refueling pods), plus by the French Air Force and Thai Air Force as a long-haul transport.
The trouble with the A330 is that there are hardly any on the second-hand market, and that they are quite pricy as new-build a/c (at least for air forces). The A330-200 would, however, make a hell of a tanker!
Airbus has a number of mil. projects going, like the A321, favoured by NATO for a "Joint-STARS"-type programme, and the A310 AWACS as offered to Turkey and (unsuccessfully) to the RAAF in partnership with IAI/Elta. But obviously, the mil market isn't one of their priorities - then again neither is the cargo market (where is the Airbus equivalent of the 737-300/700 Quick Change or the 757-200 freighter?).