The news over the past few weeks regarding Alberto Gonzales and the resignations and replacements of US Attorneys has generated much attention. The reasons are certainly numerous: the timing of Scooter Libby's trial, the ties that the replacements have to the Bush administration, the questions surrounding the abrupt nature of the resignations and the inevitable comparisons to the Saturday Night Massacre back in 1973.
Until recently (as with many actions regarding political and governmental appointments), there was a general process that was followed when a candidate is suggested, nominated, appointed and confirmed as a U.S. Attorney. Both the Legislative Branch and the Executive Branch are involved in this process.
There are 93 US Attorneys (including Puerto Rico and Guam), with each Attorney representing a "district." Obviously, some states have more than one district while some states have only one district. The following basic information is from the US Department of Justice's web site (emphasis added):
United States Attorneys are appointed by, and serve at the discretion of, the President of the United States, with advice and consent of the United States Senate.