The 33-year-old, who left Oldham earlier in the summer, has been in talks with County for the last three weeks and his arrival follows that of Luke Rodgers, who signed a two-year deal 24 hours earlier.
County manager Ian McParland said: "It's been a long time coming, but we're delighted Lee has signed for Notts County.
"He's a goalscorer, he's experienced and he fits the bill for what we need at Meadow Lane.
"To attract a player of Lee's calibre is another major coup for us and following on from signing Luke Rodgers I'm really pleased we've
managed to get Lee signed up."
The former West Brom and Coventry frontman joined Oldham in the summer of 2007, but spent the final three months of last season on loan at Championship side Blackpool.