There's an interesting post over at Universe Today, "When Our Galaxy Smashes Into Andromeda, What Happens to the Sun?" It refers to a recent article (PDF) by T.J. Cox and Abraham Loeb in which they simulated the impending collision and looked at the possible consequences for our nearest and dearest star (and planet). I was interested in this because I recently played with some galaxy collision simulations and wrote about them here.
It doesn't look too bad for the sun in these simulations. It will be more of a galactic sideswipe than a head-on collision, and we may move to a different neighborhood. But no rush to pack or anything - the first sideswipe will be in about 2 billion years.
The animated gif is linked from the Galaxy Crash web site (that's the Java simulator).