The US has services available that lets you receive near real time NEXRAD ground based weather radar images (incl. looping to see the movement trend) + METARs & TAFs. The one we use uses a colour PDA, a GPS connection & the subscription satellite weather receiver. Garmin's newer panel mount GPS/NAV/COMMs are also capable of displaying the information if you install the necessary extra bits.
After a few teething problems getting it set up the system is wonderful! Flying charter around the SE USA & Bahamas it lets me see where the weather is, where lightning has been observed, whether the Wx is VFR, marginal VFR or IFR, tap on an aerodrome to see airport details & weather reports/forecasts etc.
The major limitation is the resolution of the NEXRAD image. It's not quite as good as an airborne Wx radar for picking a way around a TS or +RASH but then the Wx radar doesn't give as big a picture of the weather system.