The February issue of the Review of Economics and Statistics contained an article by Missouri's Emek Basker analyzing the effects of Wal-Mart on job creation. Abstract below (full version can be downloaded from SSRN):

This paper estimates the effect of Wal-Mart expansion on retail employment at the county level. Using an instrumental-variables approach to correct for both measurement error in entry dates and endogeneity of the timing of entry, I find that Wal-Mart entry increases retail employment by 100 jobs in the year of entry. Half of this gain disappears over the next five years as other retail establishments exit and contract, leaving a long-run statistically significant net gain of 50 jobs. Wholesale employment declines by approximately 20 jobs due to Wal-Mart's vertical integration. No spillover effect is detected in retail sectors in which Wal-Mart does not compete directly, suggesting Wal-Mart does not create agglomeration economies in retail trade at the county level.

Yep--contrary to the rants of the anti-Wal-Mart hysterics, Wal-Mart doesn't, on net, "destroy" jobs. Of course, they'll whimper and whine about the pay or the benefits or ...

Of course, regardless of Wal-Mart's real or imagined effects, the real issue is liberty--things like freedom of association, freedom of exchange, ...

ADDENDUM: Basker also has a paper examining Wal-Mart's effect on prices. Not surprisingly, Basker finds that Wal-Mart does push down retail prices--a big benefit to lots of poor consumers, but you won't hear that from Wal-Mart bashers. The paper is available here.