subd lib eagle cad
ok, it's not that hard. first make a symbol - open up the lib editor, create a new symbol called pic18F452. Click on the pin tool (bottom of the left hand tool panel) and lay down 40 pins in 2 columns. for the right column, rotate the pins. Click on the name tool and then click on each pin, renaming it to the appropriate name. Now, use the wire tool to draw a box around the pins. next, add the text ">NAME" in the names layer and ">VALUE" in the values layer.
Now, find a 40 pin (or what ever you want to use) package and copy it to the library where you created the symbol. Next, click on device and create a new device named pic18f452. In the panel to the left, click on the "add" button. select the symbol you just created. it will apear in the left hand pane. Then click on the "new" button of the lower right panel and select the package you want, it will aear in the upper right panel. Finally, click the connect button and connect the pads of the package with the pins of the symbol. take care to get them right.
finally, in the schematic editor, either do a "use" or "Update" for the library that has the new part you just created.
The 452 is only a 40 (dip or plcc) or 44 pin (tqfp) part. Not 18 or 28.