No real difference just a varying syntax. In general the second form is frowned upon in most formatting conventions but that is more organisational than anything else.
There is, however, one thing the second form (i.e. putting the brackets on the variable rather than the type) will allow you to do that the first won't however (and this is general declaration stuff nothing to do with main itself) and that is something like this
int a, b, c;
where a and b are normal ints and c is an int array.
That, however, is also frowned upon in most formatting conventions. Again, though, this is more organisational than anything else.