Long equation in a two-column article

[Matias Freytes]

Hello,
        I have a two column article (ieeetrans.cls) and I have a
very long equation. I'd like two span the equation over both
colums:

    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
      my long equation (1)
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb
    aaaaaaaaaa  bbbbbbbbbb

Any hints?

thanks in advance.
Matias.