You need first to check what subscription type you are.
U2.com paid members are split into 3 groups,based on loyalty, u2.com have already e-mailed paid members to confirm which grouping they fall into, you should have got this e-mail over a week ago.:
1) Horizon subscribers - these are members who joined prior to October '08 approx - (exact cut off is unknown) or before that.
These subscribers can buy presale tickets(up to 4 tickets for one gig) on the first day of the presale.
2) Breathe subscribers - these are members who joined before the tour was announced, but later than 1) above.
These subscribers can buy presale tickets (up to 4 tickets for one gig) on the morning of the second day of the presale.
3) Boots subscribers - these are members who joined after the tour was announced.
These subscribers can buy presale tickets(up to 4 tickets for one gig) on the afternoon of the second day of the presale.
The exact start time of the presale has not yet been announced, but they are confirming the dates and times here later today:
http://www.u2.com/tour/index/
But, it is
expected , and I repeat expected that the Preasales for Dublin, London, Nice, Paris and all UK gigs will start tomorrow Tuesday March 17th at 10am for Horizon subscribers, Breathe subscribers can buy from Wednesday morning March 18th, and Boots subscribers can buy from Wednesday afternoon on march 18th.
Check the website link above as this will have all the details and times, and this page will also have the links to where you can buy your presale tickets, so start on this page and not on ticketmaster.ie