597's will slide right off the 590 rims. Not particularly any improvement either - most 597's out there are no better then the cheap 590's available at most places.

-Kurt

P.S.: Don't forget to take brake reach into account. Unless you have a pair of the longest Weinmann or Dia-Compe centerpulls on hand, you might find the additional brake reach not sufficient. Yyou'd probably be best off finding another cheap frame in your size before going any further, IMHO.