Is it possible to have a 2nd bootable HDD on a Dell Latitude C610 / C510?

i don't think so..you might have to take it to the shop and tell them you want to add a extra hard drive in your laptop
or you can parition your hard drive, and install the new os on another parition.

Although it is possible, dell do not support upgrades, unless done by one of their technicians... Your best best is to partition the hd.
Spinal

Partitioning the HD is not possible because it's a company laptop. Going overseas and want to be able to use my company laptop in leisure. They have ok'd the 2nd bootable hd, but no assistance on setting it up.

Ok, I''ve just gone through some Dell manuals, officially, Dell does not support a second HD. But realistically, as the laptp has 2 separate batteries, a second HD could be fitted. Although, I doubt your company would allow it as it would totally void the warranty. BAsically what you would want to do is remove a betetry, open it, remove the contents, replace it with a hd, add a generic controller card, and pass the wire inside to the parallel port or something similar. If you were handy with BASIC, you ccould also make ur own controller card that would handle both HDs. If you need extra help/info on modding the battery, just shout. You could also try an external HD. Sadly, as I said, dEll does nto support a second HD (look at the other debate, entitled "Award Winning Service???", its a debate on how "good" dells service is (it may be good, but its horrible for upgrades)
Spinal

Well there is a media slot available if I take the cd rom out. In the BIOS it gives the option of booting from the media slot. If I were to go this route, how would I get the OS on the media slot hd without a cd rom?