* Rules apply for companies getting funding in the future

* Obama criticizes pay "irresponsibility"

* Geithner to hold conference on compensation reform

* Wall Street observers critical of move

By Jeff Mason

WASHINGTON, Feb 4 (Reuters) - President Barack Obama took on bailed-out Wall Street firms on Wednesday, setting a $500,000 annual cap on pay for top executives at companies receiving taxpayer funds and tapping popular anger over financial sector excesses.

Obama said more measures would be outlined next week to overhaul the crisis-hit U.S. financial sector, which has been propped up with billions of dollars in public funds.

"This is America, we don't disparage wealth. ... What gets people upset, and rightfully so, is executives being rewarded for failure. Especially when those rewards are subsidized by U.S. taxpayers," he said.

The president won support in Washington, with some Republicans who were critical of the financial sector bailout praising the move. But Wall Street critics said the compensation cap was a political gambit that could prompt a talent flight from affected firms.