I have a mother that is older than 70. she exists off of Social Security and has no other income. She has not had to file a tax return for years but will need to file this year to get the $300 tax rebate the government is giving. can she use the 1040ez form?

For stimulus rebate, she must file 1040A or 1040. Normally, it such cases, you file Form 1040A.

Read this:
Tax News: Are you eligible for the 2008 Stimulus Payment? (http://taxgeek.spaces.live.com/blog/cns!2EEA05E22BF141DC!114.entry)