See page 11 of the IEEEtran manual; there is an example at the top of the page.
Now, the double column equations are
defined on the page prior to the one
in which they are to appear (and in
this example supposed that they are to
be equation numbers six and seven):
% ensure that we have normalsize text
% Store the current equation number.
% Set the equation number to one less than the one
% desired for the first equation here.
% The value here will have to changed if equations
% are added or removed prior to the place these
% equations are referenced in the main text.
x = 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19 + 21+ 23 + 25
+ 27 + 29 + 31
y = 4 + 6 + 8 + 10 + 12 + 14 + 16 + 18 + 20+ 22 + 24
+ 26 + 28 + 30
% Restore the current equation number.
% IEEE uses as a separator
% The spacer can be tweaked to stop underfull vboxes.
The result of which is shown at the
top of this page. This technique
allows the definition of the equations
to be positioned arbitrarily as needed
so that the (floating) equations will
appear where desired. The “[!t]”
option forces LATEX to do its best to
place the equations at the top of the
next page. Had it been “[!b]” instead,
then the stfloats package would need
to be loaded and the \vspace command,
followed by the \hrulefill command,
would have to occur before the
equations in the figure.