The resource CD is provided with every laptop bought. Currently Dell does not offer the possibility to download the same resource CD that shipped with your laptop. Of course, for a small fee I think it could be possible because I have seen other developers using this method. Instead of the resource CD, you will always have support for your laptop regarding manuals, drivers, troubleshooting questions, etc.
Please contact Dell in order to obtain additional info about an additional copy of the Dell Resource CD.