Everything you need to know can be found on the Dell support website (support.dell.com)
Maual for the Dimension 4700 (ftp://ftp.dell.com/Manuals/all-products/esuprt_desktop/esuprt_dimension_desktops/dimension-4700_owner%27s%20manual_en-us.pdf)
You can put a maximum of 4GB, (4x1GB modules) 400MHz or 533-MHz (PC2-3200) DDR2 sticks.
And yes, any PC2-3200 400Mhz DDR2 will work, (max 1GB per module)
The manual will tell you which slots to plug them into.