Well, my opinion differs from bb's slightly with regards to the timing of the TOEFL..
As rightly said my most, TOEFL is nothing compared to the GMAT..Hence in my opinion, if one has prepared seriously for GMAT, TOEFL can be taken any time after the GMAT. Do note that there is a "Listening" and "Speaking" section on the TOEFL which is not like anything on the GMAT. However it is quite easy and should be a cakewalk after a couple of sample exercises..
One of the important points to remember with regards to TOEFL is that ETS takes a loooooong time to send out the TOEFL scores unlike GMAC. The official GMAT score report comes out within 7-10 days, however the official TOEFL score report comes out only after about 45 days (at least for internationals like me). ETS also takes the same amount of time to send the official score report to the institutions chosen by you.
Hence in summary, in my opinion a couple of things should be kept in mind -
1. If the colleges you are targeting require TOEFL, then appear for TOEFL a couple of months before the deadlines you are applying to..
2. If you have plenty of time on hand, then focus on GMAT first and once you ace GMAT, taking TOEFL will be like a stroll in the garden...
Just my two cents...