Unless you have DigiTranslator on your rig you're not going to be able to make an OMF export anyway so don't sweat that part...
When you decide where you're going to mix (I read your other post) ask if you can come in ahead of time with your hard drive and see if everything loads up ok on their TDM system, shouldn't be a big problem as 99% of pro studios would rather know how you are going to deliver ahead of time and help you work things out then have you appear the day of the mix with a nasty suprise under your arm
As far as I know and have read it is no problem to load a LE session on a TDM machine (backwards compatabilty with PT's in very solid), but you should check on availability of any plug-ins that you are using that the studio might now have loaded. The biggest difference is that the TDM system will probably have a higher track and voice count and physical outputs than your LE so you might be able to spread your tracks out more for the mix.
Good Luck!