Barcelona is great at any time of the year. Great bars, superb restaurants, wonderful shopping, good beaches, loads of history and culture. (There's also a great integrated transport system. A cheap day ticket, called a 'T-dia' covers the excellent metro service, the modern buses and the speedy trams).
easyJet fly directly to Barcelona from Belfast, Bristol, East Midlands, Liverpool, Gatwick, Luton, Stansted and Newcastle.
Ryanair fly to Girona (which is 'an hour and a bit' away from Barcelona on the express bus) from Prestwick, Newcastle, Tees Valley, Blackpool, Liverpool, Manchester, East Midlands, Birmingham, Bristol, Luton, Stansted, Bournemouth and Newquay.
Ryanair also fly to Reus (again, an hour and a bit from Barcelona on the direct bus) from Prestwick, Liverpool, Birmingham, Luton and Stansted
For cheap accommodation, go here and use the 'Additional search options' to select 'Budget hotels' and 'Guesthouses':
http://www.hostelworld.com/
Barcelona tourist info:
http://www.barcelonaturisme.com/?go=jN7uAYLx/o IJaWVQCb4ZU93ygJVYLOpRQdvyIue/wAW6Ddhyhal0Y8Jy bdczumN4RSbo3CRL94sJBt7u1Kc=
Chris