Here are some links to websites that you might find useful.

Brighton & Hove Council
Brighton & Hove City Council
Trust for Developing Communities
Trust for Developing Communities - Community Development and Youth Work.
Sussex Wildlife TRust
Sussex Wildlife Trust - Leading nature conservation organisation covering East Sussex, West Sussex and Brighton and Hove.
Resource Centre
The Resource Centre - A charity serving community and voluntary sector groups in Brighton. For all your printing and publishing needs. Also equipment hire.
Tuesday at Friends
'Tuesday at Friends' meets every Tuesday between 2:30 and 3:30 pm during term-time at The Friends Meeting House, Ship Street, Brighton BN1 1AF - Tel: 01273 770258, The meetings are open to everyone, young or old - admission £1.50 at the door. There is no need to book - just turn up.
Come and join us at the Brighton School Of Samba .. no experience needed and all ages and abilities welcome ... we perform at all the big events in the city and beyond and we are always looking out for new dancers and drummers (Bateria) see the website (www.brightonschoolofsamba.org.uk) or Facebook page (Brighton School Of Samba) for info 
CRI
CRI - Substance misuse and harm reduction service, Brighton
Safe In The City
Multi-agency crime prevention for Brighton & Hove.
Brighton Permaculture Trust
Brighton Permaculture Trust - Provide services to communities wishing to plant orchards.
Community and Voluntary Sector Forum
The Community and Voluntary Sector Forum (CVSF) has a positive track record of supporting and promoting the third sector in Brighton and Hove.
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"Friends of Craven Wood". Organisation conserving woodland on the west side of Whitehawk Hill. Friends of Craven Wood are always looking for new volunteers! We (normally) run workdays on the first Saturday of each month from 10am-1pm.