>>my line illustrations at 1000 dpi<<
Now line drawings are a different matter. As they are usually just 1-bit images (i.e. pure black and white only) to get crisp images they DO need to be a very high resolution. In fact, they can be thought of in the same way as text. However, because they don't have any colour information, their file size can be quite small, even at very high resolutions. But resolution isn't really the issue here.
What you need to do with these line drawings is to save them in EPS format out of whatever vector program you create them in (Fireworks, was it?). The EPS format retains all vector qualities of the file. The EPS files can be placed in Pagemaker BUT bear in mind that what you see on screen are not the actual EPS images - they cannot be viewed as such - but the 'preview' image you can create when you save the EPS file. On a PC, this is usually a TIF, although you can choose what sort of preview you save. For example, in Illustrator, the preview can be 'none', black&white TIF or colour (8-bit) colour TIF. If you have the same choices in Fireworks, I would choose the B&W TIF to save in file size.
So be aware that the EPS may not look good on screen as you are only seeing the preview. There may even appear to be a white bounding box if placed against a coloured background (which can be made to 'disappear' if the image is rotated by 0.01 degrees). You must have a postscript printer for the EPS to print correctly. If you don't have a postscript printer, only the preview will be printed.
>>set the PDF they want for printing at 300 dpi<<
If you are then making a PDF from the PM file with the placed EPS images, make sure that when you choose the Distiller job options, you choose the 'Press' setting. This will preserve all raster images (not EPS files) at 300 dpi. The EPS files will look fine as they don't have a 'resolution'.
However, bear in mind that when viewing the PDF on screen, the graphics that were EPS may look rather pixelated, but will print beautifully - even on a non-postscript printer!!. I don't know what version of Acrobat you have, but in older versions, the default display setting was to NOT smooth line art (how stupid is that?). You can change this under Edit>Preferences>Display in V5 but I think they changed the default in V6.
If you need more info on making the PDF, or anything else, just ask.