lancel,
Of course it depends on who you talk to, but the following are some excellent resources:
Essential:
"Analysis and Design of Flight Vehicle Structures" by E.F. Bruhn. Last printed in 1973 but still available from many sources. The "Bible" of airplane stress analysis. Also try to get a copy of Bill McCombs' supplement to Bruhn "for increased scope and usefulness".
Handy to Have:
"Airframe Stress Analysis and Sizing" by Michael C.Y. Niu. ISBN 962-7128-08-2. Look for the second edition (1999)which corrects several errors compared to the first edition.
"Practical Stress Analysis for Design Engineers" by Jean-Claude Flabel. ISBN 0-9647014-0-5. A good entry-level book for stress analysts.
There are many others, of course, depending on your particular emphasis. Roark's book of stress/strain equations, Peterson's book on stress concentrations etc.
Ask the senior engineers in your new stress group which references they use the most in the office; that's probably going to be your best guide.
Good luck.
SuperStress