The Court issued a press release in which Justice Souter’s colleages expressed their best wishes towards him. I’ve reprinted them in full below:
STATEMENTS FROM THE SUPREME COURT
REGARDING JUSTICE DAVID H. SOUTER’S RETIREMENT
May 1, 2009
Chief Justice John G. Roberts, Jr.:

Justice Souter has served with great distinction on the Court for nearly 20 years. His desire [...]

Justice Souter has officially given President Obama notice of his intent to retire at the end of the current term. His notification seemed to suggest that he will not remain in his position until his successor is seated.
Thanks to SCOTUSblog, we can see the Court’s press release here and Justice Souter’s letter here.
You can read [...]

Despite all the talk of Justice Souter’s importance to the Court, the proposition that Justice Souter has had a minimal impact on the Court’s most controversial issues is generally true. Since the beginning of OT06, Justice Souter has issued just 1 of 39 5-4 opinions and this lone 5-4 majority opinion was handed down less [...]

It would be naive to think that Justice Souter’s replacement won’t have a major impact on the future of the Supreme Court. At a minimum, if President Obama were to simply hit the refresh button on Justice Souter and replace him with a 55-year old version of himself, the liberal wing of the Court would [...]