Just a slight improvement on Chris's answer...
Ctrl+H, then replace:
{:b*}{[^:b]*}:b*=:b*{[^:b]*}:b*;
with:
\1\3 = \2;
(better handling of whitespace, esp. at beginning of line)
EDIT:
For Visual Studio 2012 and higher (I tried it on 2015):
Replace
(\s*)([^\s]+)\s*=\s*([^\s]+)\s*;
with:
$1$3 = $2;