Broadband is seen as the future of the internet
The money is additional funding aimed at bringing the high-speed data-transfer technology - often using existing copper-based telephone wires - to all parts of the country.
The promotion of broadband technology is one of the main target's of the Assembly's ambition to encourage knowledge-based economic development in Wales.
And it is hoped the move will help bridge Wales's growing "digital divide" where just 19% of people are connected to the internet, way below the UK average of 33%.
Assembly First Minister Rhodri Morgan claimed the cash puts the assembly ahead of Westminster for broadband services - around 10 times faster than modem-based computers - within easy reach of people in Wales.
The money will be spent over the next six months to create a broadband Life-long Learning Network, designed to turn around Wales's poor take-up of broadband which is currently the lowest in Britain.
Of the £18.4m announced, up to £8.5m will go towards providing a high-speed network and broadband internet access for each of Wales's 22 local authorities and for extending provision in further and higher education.
This programme will have a further £4m from the assembly in the following financial year.
But the largest share of the money, £9.9m will go towards providing interactive multi-media equipment for every primary, secondary and special school in Wales.
Specifically, this will include a "whiteboard" - a two-way electronic notepad for use in lessons video-conferenced to a number of locations - and a data projector.
Online services
In addition to the new money, the broadband roll-out programme will soon include £2.7m from the DTI as part of Westminster's UK-wide promotion of the technology.
The assembly's £6m funding commitment to broadband in the next financial year also includes £2m for training for broadband users.
In return, it expects Welsh business to benefit from the public sector spending through the Welsh Development Agency offering broadband access for small and medium-sized firms.
Broadband is seen as the key to firms offering value-added online services such as interactive promotion and purchasing.
IT skills
By increasing e-learning opportunities in schools, the network should also develop youngsters' IT skills.
First Minister Rhodri Morgan said: "This is a made-in-Wales policy which I believe to be the most far-reaching and significant investment in broadband made by any UK government.
"Easy access to fast internet services will become increasingly important in the future and it is essential that all areas of Wales are able to take advantage of the benefits of this new technology."
Assembly E-Minister Andrew Davies added: "It will bring broadband into schools for the first time and ensure that rural areas of Wales do not lose out on the technology of tomorrow."