How can I make the drives mounted with ntfs-3g to apear in the file browser in the places tab and on the desktop as it happens with the other drives - floopy, usb flash memory,...

Although the drives are mounted and can be viewed through /mnt/C/ and /mnt/D/ they're not shown in file browser "computer:///" and in places tab
I want that fedora will recognize those drives as Drives and not as folders.

Sorry, this is the Windows way of thinking and not how things are under Linux all drives (hard, floppy, CD/DVD, external, USB and etc) and partitions appear as a single filesystem. The concept of 'partitions as drives' is an old odd concept which is confusing and only applies to Microsoft created and influenced Operating systems (DOS, Windows, OS/2 for example).

The term 'folder' is also a Windows term and not correct in any case, partitions are partitions, directories are directories and subdirectories are subdirectories.

Feel free to (maybe) edit the /etc/fstab file and add icons for the partitions to suit your desire. For example, I have KDE desktop icons for my Windows 2000 Professional "drives" added for personal preferences myself.