Is Excel VBA the same as VB.NET
No, Excel 2003 and 2007 use Visual Basic for Applications, which is a variation of Visual Basic 6. This is an enormous change from VB.NET. See here for more details about specific differences.
No, the only similarity between VBA and VB.NET is the similar-looking syntax.
VBA is similar to Visual Basic 6, which is obsolete since about 1997 (?), so VBA is not a very modern language.
VB.NET is a modern language, having the same capabilities as C#, but the syntax is terrible, so I personally prefer C#.
VBA is an interpreted language, while VB.NET is compiled.
If you are interested in Office programming, you might consider doing your next Office project in VB.NET and VSTO, which is the modern alternative to VBA.