The assembly wants to bring Welsh libraries into the 21st Century
A three-year strategy to modernise libraries across Wales will be launched by the Welsh Assembly Government later.
£10.5m funding for the Libraries for Life programme had already been announced in March.
It aims to improve facilities and allow more than 20% of libraries to open at least 10 hours a week by the year 2011.
Heritage Minister Rhodri Glyn Thomas, who is visiting Wrexham, said it would help create a "21st Century library network".
Mr Thomas is due to open the refurbished Rhos Library in Wrexham.
He said: "Libraries enrich the lives of people in Wales at all life stages so it is very important that we look after the network and make the right investments in facilities, staff development and marketing to keep libraries vibrant, relevant and accessible.
"This programme provides a framework for the Assembly Government, local authorities and all types of libraries across Wales to come together to create a truly 21st century library network."
The assembly government said the three-year plan was aimed at modern lifestyles and people's changing needs.
The scheme includes upgrading internet facilities at libraries, introducing Wi-Fi, as well as allowing users to search for "elusive" books via an all-library search system.
The National Library of Wales is also developing an online "virtual" library.
It will include information about local library events and access to online newspapers and reference books.
Many libraries, like Wrexham, already offer free internet access
The assembly government wants more people to use their local libraries, and for libraries to make it easier for members to borrow from elsewhere.
Training will also be provided to library staff to boost their skills.
The announcement received a warm welcome from library users in Wrexham Arts and Library Centre, which often receives between 1,100 to 1,200 visitors each day.
Henry Irish, 77, from Broughton in Flintshire, said: "I can't see very well so I use a lot of talking books.
"The selection here is fantastic. Without this library I'd really suffer, so to spend more money upgrading the places is a good thing."
Ken Lacey, 74, from Wrexham, said: "I use the library mostly for the internet and I know a lot of other people do.
"It's a great idea to spend more money. Libraries provide very valuable services."
Paula Cunniffe, from Wrexham, said: "I use the library mainly for books. Sometimes I'll come here every week.
"It's a very popular service and spending money on libraries can only be a good thing."
Mr Thomas will officially open the refurbished Rhos Library, Wrexham, at 1400 BST.
The library now has improved lighting and shelving, a disabled toilet, baby changing rooms, more books and DVDs for hire following a £100,000 Welsh Assembly Government grant last year.