Most modern cards nowadays come with 1x VGA output (CRT and some TFT cables) and 1x DVI output. You can plug most TFTs straight into the DVI and get an adaptor to plug them into the VGA (or vice versa, should your new monitors use vga connectors). A "splitter" device would just clone the signal giving you an identical picture on each screen.
Ideally you will want to use DVI with your TFT screens; this allows the screen to automatically configure itself for "perfect geometry" ie a perfect 4:3 image. For this to happen on both monitors, both "heads" on the graphics card will need to be DVI. You didn't specify AGP or PCI-Express so I'll assume AGP. In this case, a card such as
this one will be sufficient. Note that you can purchase 256mb versions of this card (at a price) which may be helpful for graphics intensive apps.
As for monitors, none of the samsung 19" LCD's below £400 appear to have DVI. I'm no expert on LCD screens however, since you mention you do graphics intensive stuff (photoshop) it would be worth noting that the colour reproduction on LCDs does not compare to a traditional CRT at the moment. If you do a lot of design for print, expect the colours you see on an LCD/TFT to differ from the hard copy.
For the most accurate colour reproduction, at the expense of time setting up geometry, look for a CRT. You'll be able to get a much larger working area with a CRT than an equivelantly priced LCD. I'm not sure of any CRTs using DVI as a connection, possibly some of the high end Sony models will.
Setup within windows couldn't be easier; for increased desktop space just activate the second monitor in the display properties section. Specialised modes can be found in the graphics cards advanced driver settings, depending on the chipset (nvidia or ati).
The triple-head system I have set up at the moment consists of one CRT connected to the VGA, one CRT connected to the DVI via an adaptor, and one TV connected to the S-Video out socket on the back of the card. In Windows this will allow you to have the taskbar on one screen and reposition application windows onto other monitors as required. In a linux setup, this will allow you to have a seperate X-Server running on each monitor, almost like having seperate PCs.