Achieving nirvana is to make earthly feelings like suffering and desire disappear. It's often used casually to mean any place of happiness, like if you love chocolate, going to Hershey's Park would be nirvana. On the other hand, if you're a Buddhist monk, it may take you years of meditating to reach nirvana.
Is it possible to attain nirvana?
While nirvana is possible for any person, in most Buddhist sects only monks attempt to achieve it. Lay Buddhists -- Buddhists outside the monastic community -- strive instead for a higher existence in their next life. They follow the Noble Eightfold Path and help others, trying to accumulate good Karma.
How do I find nirvana?
Nirvana can be attained via any spiritual path within any religion, that is whether the religion or group believes in and teaches about Nirvana or not. There are many examples of this happening. For example there are awakened Christians who have a particular view about what/who God is due to their awakenings.