You can create an EPS file with a transparent background using Adobe Photoshop CS5. In fact, if you intend to import a Photoshop PSD image into a page layout program such as Adobe InDesign, you must first prepare the PSD image for export to the EPS format to preserve transparency. To do that, you must create a "clipping path" that defines the visible area of the image. Even if the background of the PSD image already is transparent, you must define the clipping path. Then you can export the file to the EPS format while maintaining transparency.
Create the Clipping Path
Open Adobe Photoshop, then open the PSD image or some other type of image that you intend to export as a transparent EPS.
Go to the Toolbox, Click the "Pen" or "Shape" tool, and then click the "Paths" icon in the top options navigation bar.
Draw around the intended visible area of the image, carefully outlining its edges.
Click the "Clipping Path" option in the "Paths" panel, and click "OK" to save the new clipping path as a work path.
Convert the File to EPS
Click the "File" option from the top navigation bar, and click "Save As."
Click the "Save as Type" drop-down box, then click the "Photoshop EPS" option.
Click the "Save" button. The EPS dialog box opens.
Click "TIFF (8 bits/pixel)" for the "Preview" option, then click "ASCII85" for the "Encoding" option. Leave all other EPS options as their defaults, and click "OK." The file is saved as a transparent EPS document.