If in 1945 Stalin had issue an order to NKVD 'Bring Wernher von Braun to Moscow alive i will not tolerate any failure" and NKVD send a special team to carry the order and succesed. Now in the hands of the Russians would von Braun will be collaborated and revealed all the secrets of Nazi rocket technology and if yes what the impact for cold war and Soviet space programe
[In honor of our 2011 Halloween Necromancy]
Any NKVD team that can break through those German lines can probably abscond with only one German.
So, Dr. Von Braun is in Soviet hands. He'd probably have 'creative differences' with the Soviets once they start going their own way in development (with the R-7 by 1954). His OTL aversion to clustering may manifest itself in an opposition to the use of strap-on boosters on the R-7. If he's not careful, he may find himself taking a bullet when he's no longer useful.
What happens in the US without Dr. Von Braun? Redstone will probably still be developed in some form; it was really just a really big V-2 IOTL anyway. Explorer is the logical outcome.
But Von Braun did a lot to convince the US government to go to the Moon as the logical way to one-up the Soviets. He was also a big science popularizer in his day. Without his long, well-illustrated articles on fully reusable space shuttles and rockets to the Moon and Mars, the US rocket program as a whole gets less exposure prior to 1957.
Von Braun was also a big opponent of the proposed break-up of his team before the Army's rocket labs were transferred whole to NASA. Without his big-name opposition, there's a chance that the Germans will be divided between NASA and the Army, and some might stay with the latter branch.
Von Braun's own fate: Assuming he dies at the same date as IOTL due to health reasons, he is largely unknown outside the Soviet engineers themselves. They will remember him as an important contributor to the Soviet military space station programs, as the moon race might be entirely averted ITTL. However, due to the heavily nationalistic and ideological nature of the Soviet information system, he may remain entirely unknown to most Russians, as it would not do for such Revolutionary triumphs of the Motherland to be owed even in part to a German. He might even be barred from leaving the country, or attending international space engineers' conferences.