NAVMAN do this pda with Windows Mobile. click here
It does not have GPRS/ GSM though, so you would have to connect to a mobile phone using the IR port.
Alternatively, try the TOM TOM bluetooth GPS receiver that connects to Nokia 6600/ Orange SPV phones. The GPS unit is relatively cheap (£<200)and you can get he phones for free if you subscribe to an orange contract (both will support email - the SPV uses Windows Mobile 2003). Try here click here
I'm sure others will have alternative methods so good luck!