Understandably, there is a lot of interest on the impact of migration and remittances on the Nepalese economy, which receives remittances to the tune of 25% of GDP and was the third largest recipient (% of GDP) in 2011. I see a lot of numbers thrown around to justify various points (including illogical and inconsistent arguments), and I too get a lot of questions on the data and the impact on Nepalese economy.
Below is a chart showing remittances data sourced from Nepal Living Standards Surveys (NLSS). And yes, there are internal remittances as well!
More on remittances in Nepal here (dig in the archives for information, data and analysis!). A recent Al Jazeera news story here. And, here is a link to a research paper titled 'Remittances in Nepal: Boon or Bane?'.