It worth take a look at MCS-51 derivatives from Hyundai Electronics (now Hynix Semiconductor).

http://www.hynix.com/eng/produ...1C7432.pdf

HMS91C7432 features and functions

-- Complete TCP/IP protocol suite
-- Built-in e-mail function
-- Standard SMTP protocol stack
-- Standard POP3 protocol stack
-- Standard PPP protocol stack to facilitate dial-up network log-on
-- Standard DNS protocol stack, resolve URL with dynamic DNS service
-- Serial built-in modem driver
-- Support V.90 56K flex modem or lower speed
-- 8-bit parallel interface to user application
-- Serial DTE port for easy modem interface
-- 5 volt or 3.3 volt operating voltage
-- 20 pins SOP package
-- Power-down mode to 5uA max
-- 96Kb SRAM (12Kx8) for communication and buffering.
-- Full duplex UART
-- Speed of up to 11.0592 MHz

The HMS91C7432 is available now in a 20pin SOP package and is priced at $2.95 in quantities of 10K