Financeprofessor.com recently highlighted this article in Financial Engineering Today titled "Sox It To Them.
It first lists many of the new requirements under the law, such as increased auditor independence, bans on auditors doing certain types of other work for audit clients, CEO & CFO certification of financial reports, accelerated reporting of insider trades, and so on.
However, the most interesting part of the article is its questioning of the commonly held belief that SOX imposed excessive implementation costs on companies.
There is some evidence that going-private transactions increased in the post-SOX period. For example, see this piece by Engel, Hayes, and Wang, titled"The Sarbanes-Oxley Act and Going Private Transactions."