Gerard Houllier signed the pair a couple of years ago but sent them out on loan to French side Le Havre last season.
After the Seine Bay club were relegated, Houllier decided the time was right to bring the 18-year-olds to Merseyside to begin their Anfield education.
The teenagers have been introduced to the rest of the squad and are looking to make their mark on English football.
"I talked with Florent and we know it will be very difficult," said Le Tallec.
"We will have to adapt to English way of life.
"But we are young. We are here to improve, discover another style of playing.
"Yesterday the coach introduced us to the group. It went off smoothly, we were really welcome.
"The day before, we had our medical examinations. We felt like we were in another world."
Le Tallec has been handed the number 20 shirt in the first-team squad, while Sinama-Pongolle will wear number 24.
The teenage pair, who are distant cousins, born just a week apart, have been together since the age of nine and have represented their country's youth teams to devastating affect.
They were the two best players in the tournament during the Under-17 World Championships in 2001, and helped France to lift the trophy.
Le Tallec and Sinama-Pongolle will now be hoping carry on their relationship on the pitch to develop into a deadly duo in the Liverpool first team.
