I work for Gene Tools. This describes a method using one of my company's products.
We tried staining actin using an anti-actin antibody fragment (50kD) labelled with Texas Red and delivered using the Endo-Porter delivery reagent. The cells we imaged were live. The cytoskeletal staining looked very nice through the scope. This offers a method for cytoskeletal imaging with minimal perturbation of the cytoskeleton.
Cells vary in their tolerance to Endo-Porter; for most cell types there is a concentration window allowing delivery without significant toxicity. We used HeLa cells.
Here is a description of Endo-Porter: http://www.gene-tools.com/node/24
Uptake occurs by endocytosis, so you would put the cargo (fluorescent antibody fragment) and the Endo-Porter onto your cells and let the mixture incubate overnight, then wash the cells and observe them the next day. You could deliver to the cells in suspension overnight, transfer them to a surface to which they will adhere and then gently wash then before observing. However, uptake is a bit better when cells are adherent (we think Endo-Porter complexes might be settling out of solution onto adherent cells).
Let me know if I can help.