Using PC and Mac together

...the main issue is fonts...

...mac handles windows fonts (truetype) better than windows can handle mac fonts. These days opentype fonts are now available, which are cross platform. Mac users tend to use these more if the work is likely destined for windows use...

...so all in all your print provider can handle windows truetype fonts or opentype fonts. In a prepress environment it is also possible to convert PC fonts to Mac fonts with specialist font software...

...actual indesign documents are cross platform, as well as all the usual bitmap formats (.eps, .tif, .jpeg, .psd, .pdf, .ai)...

...if your print provider doesn't need to edit your files then the usual method is to supply them with a print ready PDF file...

andrew

...to add to my above post...

...the real problem occurs with postscript fonts, mac can't use windows postscript fonts and vice versa, in this scenario a mac user in prepress will need to either convert the windows postscript fonts to mac format (can be hit and miss) with specialist font software...

...or they will need to be substituted with a mac version (also hit and miss)...

...so the only real sure way to maintain file appearance is to supply a print ready PDF that the print provider has to do little to no editing with...

...in some cases to make extreme edits a print provider would need to convert the PDF fonts to outline (vector shapes), but really depends on what editing needs to be made. They will most likely charge for any time consuming editing to supplied artwork...

andrew