Max number of files per directory recommended?

Hi... I have a site that as many picture galleries... and one folder is very big. I'm a bit concerned. Will it affect my site?

Does someone can recommend me a good folder splitter for windows?

If you know the name of the file you want to access, there is almost no penalty. If you need to search for a file you should definately break them up in different folders.
You could use TotalCommander to Group-Mark files and then move them to a new folder.

well is the server your or you host your website at some hosting company, i have the same problem before, I have around 2000+ images in one folder and the result was the via FTP a cannot list all files, in the browser the were visible but in FTP no, so after quick phone call to hosting company the problem was solved, they have set up their servers to list only 2000 files in FTP and just update the setting for me. By the way I have never had some other problems with many files in one directory, exept previous one.