An initial fee is believed to be £100k will be paid and could rise to £200k based on appearances. Zola was in his last year of his contract at Prenton Park when the Railwaymen approached the Wirral based club for his signature.
The former Newcastle United trainee went on loan to Oldham Athletic in 2003-04 and then signed for Tranmere after his loan spell at Boundary Park.
Although he had work permit problems Zola made 96 apperanaces netting 16 league goals over a four year period.
The Congolese striker has been Steve Hollands main target of the summer and looks set to be Crewe main target man for next season.