We very recently published a paper in *Cell* which looks at TF regulatory networks in human. In addition to procedural and reference material that might help you out, data downloads are available through Cell's site, and I put together a web application that allows exploring interactions in a variety of cell types.
We also have PWMs available for discovered motifs. You could run these through a tool like TOMTOM to find TF matches across other databases (TRANSFAC, JASPAR, etc.).