Yesterday David Cameron announced that he was reopening the list of approved candidates for fresh applications, and that even people from outside the Conservative party may apply.
There are always a few plum seats that fall free at the end of a Parliament, as older MPs decide that they can't face another four / five year term and they would prefer to spend more time with their families. This time the expenses scandal is likely to create more such opportunities than usual, with the Times predicting that some 325 seats could change hands.
The selection process is also likely to be speeded up, particularly if an election is called early. I will post more details on the new procedure when they become available.