Hi, a few weeks ago I was pondering over the same question as how to WYSIWYG for the printouts on my canon I990 (old model with 7 ink cart for A4 prints). Here's a few suggestions:
Screen:
The 1st step in achieving a proper workflow with consistent color matching between the various digital medium, is to have a properly profiled monitor. This is definitely the most important as right after the shots are transferred from the cam to the PC/MAC, you'll be post processing with software tools which will require you to look the images displayed on the screen (CRT/LCD) and adjust/edit. If from the start the monitor is improperly profiled, rubbish in from you due to skewed color presented by the screen, rubbish will be printed out. Don't even be bothered with screen profilng software that depends on your eyes to judge the adjusment.. spend a few hundred bucks, get a proper profiling hardware such as Spyder2/3 or I1D2. I have both spyder2 and I1D2, I've never used the spyder 2 as i started out with the I1D2 and it does the job very well. Once the monitor is profiled, you only need to reprofile every other few weeks to months.
Printing:
Easiest way is to get the vendor provided ICC/ICM for the specified photo paper you are using. If you use the better quality paper from Canon for photo print, you can find them (the ICC/ICM for each paper) online. These are fairly good paper profiles and so far the ones i'm using from Canon has prints very very close to watch I see on the monitor (though the lightsource you are viewing the printouts with is also very important, too yellow or too white affect the hue across the print). If using Canon's ICC/ICM, just make sure you install the ICC/ICM, select the correct paper type and quality level prior to printing, and enable ICM within the print driver as you flip through the dialog boxes for print setup (WIndows). If using Mac, you need to ensure the ICC/ICM are installed and recognised by Colorsync and when your print, again select the correct paper type and quality level, let the printer manage the color profiles and allow colorsync within the print driver to handle the color matching. Don't let the graphic application handle the color profiling unless you know exactly how it works or you risk double profiling.
If however if you are using a different paper with no ICM/ICC support from the vendor, you need a printer profiler. This can come in various form of packages, some packaged with a hardware spectrocolorimeter while some require the use of scanners to profile your prints. I've both type. The winner is the one using a hardware spectrocolorimeter. Dun bother with the scanner solution which tends to be much cheaper. The color space with the scanner solution is very small giving you a really limited gamut that even if your printer can print, it is made not to print to its full potential. I'm using Printfix Pro Suite and so far my Samsung SP2020 dye sublimation print out are very good and accurate, almost rivaling my I990 which has a slightly wider gamut. Again, if got budget invest in the hardware profiler, or simply pay a bit of $$ for someone online to profile for you.
Conclusion:
Sceen:
Buy/borrow/rent a monitor profiler such as I1D2 or the latest SPyder3. However, if your monitor is not suitable (TN panels with serious color shifts and uneven lighting), dun waste $$. Buy a good monitor 1st, at least a S-PVA panel, if not the unrivaled IPS panels, OR simply get a cheap flat screen CRT monitor as they do better than most LCD.
Printing:
Got $$ buy a package with hardware profiler, or simply engage those print profiling services online which will request you to print an image sample which you will need to snail mail to them. Else search for the vendor provided profiles.
Both Mac and PC no problem with whatever options you decide to use as both workflows are similar. However, do not expect a full 100% match between the sceen and print as it will never happen.