Sujata, expanding on Mike's posting above, MML is a text-based FrameMaker file format that can sometimes be useful for conversions. Unfortunately MML is very, very limited in the formatting it can retain, so it would depend on what kinds of content you need to convert, as MML is very "restricted" in what it can represent. Here's more info (and there are certainly many other websites with additional info): http://www.cs.stir.ac.uk/~kjt/software/framemaker/ and http://www.klariti.com/framemaker/index.shtml
You might also be able to go from LaTeX to RTF to FrameMaker.
Another alternative is to use a general macro programming tool to convert from LaTeX to MML or to MIF, such as LogicTran or others.