dc current meter
If you want to make a DC Current or Voltage Digital meter, you can use an Intersil's ICL7107 (LED display) or ICL7106 (LCD display), depending on your desired display medium. Microchip also has versions of the mentioned IC's namely TC7107 and TC7106 plus an improved versions in TC7117 and TC7116. You can check the menufacturer's website about infos on this IC's. They are integrating ADC's, and are really meant for digital display. The input for these IC's are DC. The 7107 and 7106 comprise the digital processing circuitry, but you also have to provide for the analog signal conditioning portion (like attenuators) to properly interface the analog signal to the analog input of the IC.
As for the AC digital meter, you have to add a module that somehow "converts" the AC to DC, so that the resulting DC would have parameters that are proportional to the properties of the AC input. Probably you can use a bridge rectifier, or other rectifiers, or RMS-to-DC converter. Analog Devices has plenty of the latter. Hope this helps.