ISAs are tax-free investments that replaced PEPs and TESSAs. Any UK resident who is over 18 can have an ISA (although cash ISAs up to the value of £3,000 are also available to 16 and 17 year olds).
ISAs can be made up from one or more elements:
A MAXI ISA means that all elements are contained within a single ISA, whereas a MINI ISA means that elements are kept within separate ISA accounts.
The maximum you can invest in an ISA is £7,000.
The government has guaranteed ISAs to run until 2009.