By .eps, do you mean you need to convert the files to a vector format? (EPS can contain both raster and vector elements. For example JPEGs are raster but could actually be contained in an EPS file). Assuming you really do need vector art, you’re largely out of luck and will need to redraw it. You could struggle with auto tracing the JPEG artwork to vector in Adobe Illustrator, but you’ll do nothing but end up with a mess and frustrate yourself.
On the other hand, if you can stay with a raster format, like PNG, you can open the files in Photoshop, use the magic want tool to select only the black items, cut the selected black items to the clipboard. Paste those items back in on a separate layer. Hide the base layer, so that only the pasted in black lines remain. Use the curve tool to reverse the black lines to white lines. Then save as a PNG, where all the empty space not taken up by the white lines will be transparent. Whatever you place the PNG over will show through, as below where I positioned it over a green background. It was literally a 2-minute project.
That said, PNG isn’t a great format for print, so depending on what end format you really need, you might want to convert the art, along with the background color, to another format, like TIFF or PSD. Like I said, though, converting it to a vector EPS will be sloppy and I see little point in saving raster art to EPS format. For that matter, there’s rarely a reason to use EPS — it’s a format that’s largely been eclipsed by newer, better formats.