My sister isn't very internet savvy, and did not e-file her taxes on time. I just found out on April 27, and finished them for her and e-filed them. She will get a refund, but will she be penalized for filing late?

Yes, if she owed tax on her return, she will pay interest and penalty. But it will be just a few dollars. If she had a refund, she will not pay any penalty.

MukatA has it right.

Same applies for the state: penalties and interest are due if she owed taxes. If she has a refund coming, there is NO penalty for filing late.

How and where do we get the forms to file late

Go to Internal Revenue Service (http://www.irs.gov)
On the left side, select the form or click More Form and Publications.

You can also download them from Home - 1040.com (http://www.1040.com).