Flatten PSD files in PS. Convert to CMYK (in not already). Save as TIFF files.
"Place" TIFF (bitmap) files into Illustrator.
(( You'll loose all the layer editing abilities on bitmaps in Illustrator, but that's not what Illustrator is for. You can still compile layers, and layers atop the Bitmap for that purpose but Illustrator is for
"Vector" work, the complete opposite of PS "Bitmap" work. But both work hand-in-hand as described above)
Good Luck!