I've posted quite a bit about how your cover letter should come together. Here's one more piece of advice on that topic: keep your cover letter short. A concise review of your accomplishments and fit for the specific job you're seeking. No more than 500 words, or about two-thirds of a page, please.
On the other hand, it's okay to go to two pages on a resume (three if you have a lot of management or executive level experience). If you have a skill, award, or job related experience and you don't list it on the resume the recruiter won't know about it. Neither will the Optical Character Recognition (OCR) software that scans your resume and puts it into a database for skill based searches.
If you were planning on explaining about your additional skills, awards, and/or experience in the interview, then those should go in the resume too or you won't make it to the interview. By the time someone decides to interview you, they've already decided you have the basic skill set required for the position. Your job at that point is to convince them you have the right personality and outlook for the position and will play well with the team and company environment.
A great resume will have the hiring executive sold on your before you even meet. So how do you create a great resume? That's why you're reading this blog, right. But don't neglect the hints and tips given out at the major job listing sites either.