From today, all Tiscali products, including broadband and IPTV services, have been brought under the TalkTalk umbrella, with the Tiscali brand disappearing in the UK.
Existing Tiscali customers will now be shifted over to the TalkTalk network, with the process due to take about a year to complete.
In June 2009, the European Union gave regulatory approval for the Carphone Warehouse takeover of troubled service provider Tiscali. Carphone moved for the firm after a proposed deal with Sky fell through earlier in the year.
The two companies have since been working out the details of an operational merger, especially as their communication networks overlap in certain parts of the UK.
As Tiscali's network is TV-enabled following its August 2006 purchase of Video Networks, the Carphone Warehouse will use it to launch TalkTalk TV and fill a gap in its service portfolio.
However, a Tiscali spokesperson said that there will be "no changes" to the existing TV service as a result of the rebrand.
TalkTalk has already started contacting Tiscali customers about changes to their packages and tariffs to bring them in line with its own pricing structures. The firm has claimed that most customers will end up paying less than they do now, but some subscribers could have to pay more, especially if they take just standalone broadband.
"Today we welcome all Tiscali customers to TalkTalk and open the doors to a new portal. We are in the privileged position of being the gateway to the internet for millions of people and we now have the tools - the best network and best value products - to do this exceptionally well," said Carphone Warehouse chief executive Charles Dunstone.
"We're committed to giving all of our customers absolute clarity about who we are, the services we provide and the prices we charge. We want to make it very clear that being part of TalkTalk is much more than just having a different logo on the top of your bill.
"For that reason we've reviewed all of the pricing tariffs and can say from today that if you're with TalkTalk you're getting the same value as your fellow customers. For many of our customers this will mean a reduction in their monthly bills, others will see no change with the remainder getting a small increase. Any customer visiting our website can clearly see our tariffs.
"We've gained a lot from the Tiscali acquisition, most notably TV and portal expertise and some great people, but from today the brand name will disappear and all our focus is on TalkTalk and AOL Broadband customers."